TITLE:
METHOD AND APPARATUS FOR AUTONOMOUS DOWNHOLE FLUID
SELECTION WITH PATHWAY DEPENDENT RESISTANCE SYSTEM
Inventors: Jason D. Dykstra
Michael L. Fripp
Orlando DeJesus
CROSS-REFERENCE TO RELATED APPLICATIONS
None
FIELD OF INVENTION
[0001] The invention relates generally to methods and apparatus for selective
control of fluid flow from a formation a hydrocarbon bearing subterranean formation
into a production string in a wellbore. More particularly, the invention relates to methods
and apparatus for controlling the flow of fluid based on some characteristic of the fluid
flow by utilizing a flow direction control system and a pathway dependant resistance
system for providing variable resistance to fluid flow. The system can also preferably
include a fluid amplifier.
BACKGROUND OF INVENTION
[0002] During the completion of a well that traverses a hydrocarbon bearing
subterranean formation, production tubing and various equipment are installed in the well
to enable safe and efficient production of the fluids. For example, to prevent the
production of particulate material from an unconsolidated or loosely consolidated
subterranean formation, certain completions include one or more sand control screens
positioned proximate the desired production intervals. In other completions, to control the
flow rate of production fluids into the production tubing, it is common practice to install
one or more inflow control devices with the completion string.
[0003] Production from any given production tubing section can often have
multiple fluid components, such as natural gas, oil and water, with the production fluid
changing in proportional composition over ti e Thereby, as the proportion of fluid
components changes, the fluid flow characteristics will likewise change. For example,
when the production fluid has a proportionately higher amount of natural gas, the
viscosity of the fluid will be lower and density of the fluid will be lower than when the
fluid has a proportionately higher amount of oil. It is often desirable to reduce or prevent
the production of one constituent in favor of another. For example, in an oil-producing
well, it may be desired to reduce or eliminate natural gas production and to maximize oil
production. While various downhole tools have been utilized for controlling the flow of
fluids based on their desirability, a need has arisen for a flow control system for
controlling the inflow of fluids that is reliable in a variety of flow conditions. Further, a
need has arisen for a flow control system that operates autonomously, that is, in response
to changing conditions downhole and without requiring signals from the surface by the
operator. Further, a need has arisen for a flow control system without moving mechanical
parts which are subject to breakdown in adverse well conditions including from the
erosive or clogging effects of sand in the fluid. Similar issues arise with regard to
injection situations, with flow of fluids going into instead of out of the formation.
SUMMARY OF THE INVENTION
[0004] An apparatus is described for controlling flow of fluid in a production
tubular positioned in a wellbore extending through a hydrocarbon-bearing subterranean
formation. A flow control system is placed in fluid communication with a production
tubular. The flow control system has a flow direction control system and a pathway
dependent resistance system. The flow direction control system can preferably comprise
a flow ratio control system having at least a first and second passageway, the production
fluid flowing into the passageways with the ratio of fluid flow through the passageways
related to a characteristic of the fluid flow, such as viscosity, density, flow rate or
combinations of the properties. The pathway dependent resistance system preferably
includes a vortex chamber with at least a first inlet and an outlet, the first inlet of the
pathway dependent resistance system in fluid communication with at least one of the first
or second passageways of the fluid ratio control system. In a preferred embodiment, the
pathway dependent resistance system includes two inlets. The first inlet is positioned to
direct fluid into the vortex chamber such that i flows primarily tangentially into the
vortex chamber, and the second inlet is positioned to direct fluid such that it flows
primarily radially into the vortex chamber. Desired fluids, such as oil, are selected based
on their relative characteristics and are directed primarily radially into the vortex
chamber. Undesired fluids, such as natural gas or water in an oil well, are directed into
the vortex chamber primarily tangentially, thereby restricting fluid flow
[0005] n a preferred embodiment, the flow control system also includes a fluid
amplifier system interposed between the fluid ratio control system and the pathway
dependent resistance system and in fluid communication with both. The fluid amplifier
system can include a proportional amplifier, a jet-type amplifier, or a pressure-type
amplifier. Preferably, a third fluid passageway, a primary passageway, is provided in the
flow ratio control system. The fluid amplifier system then utilizes the flow from the first
and second passageways as controls to direct the flow from the primary passageway.
[0006] The downhole tubular can include a plurality of inventive flow control
systems. The interior passageway of the oilfield tubular can also have an annular
passageway, with a plurality of flow control systems positioned adjacent the annular
passageway such tha the fluid flowing through the annular passageway is directed into
the plurality of flow control systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] For a more complete understanding of the features and advantages of the
present invention, reference is now made to the detailed description of the invention
along with the accompanying figures in which corresponding numerals in the different
figures refer to corresponding parts and in which:
[0008] Figure 1 is a schematic illustration of a wel system including a plurality
of autonomous flow control systems embodying principles of the present invention;
[0009] Figure 2 is a side view in cross-section of a screen system, an inflow
control system, and a flow control system according to the present invention;
[0010] Figure 3 is a schematic representational view of an autonomous flow
control system of an embodiment of the invention;
[0011] Figure 4A and 4B are Computational Fluid Dynamic models of the flow
control system of Figure 3 for both natural gas and oil;
[0012] Figure 5 is a schematic of an embodiment of a flow control system
according to the present invention having a ratio control system, pathway dependent
resistance system and fluid amplifier system;
[0013] Figure 6A and 6B are Computational Fluid Dynamic models showing the
flow ratio amplification effects of a fluid amplifier system in a flow control system in an
embodiment of the invention;
[00 ] Figure 7 is schematic of a pressure-type fluid amplifier system for use in
the present invention;
[0015] Figure 8 is a perspective view of a flow control system according to the
present invention positioned in a tubular wail; and
[0016] Figure 9 is an end view in cross-section of a plurality of flow control
systems of the present invention positioned in a tubular wall
[0017] Figure 10 is a schematic of an embodiment of a flow control system
according to the present invention having a f ow ratio control system, a pressure-type
fluid amplifier system, a bistable switch amplifier system and a pathway dependent
resistance system;
[0018] Figures 11A-B are Computational Fluid Dynamic models showing the
flow ratio amplification effects of the embodiment of a flow control system as illustrated
n Figure 0;
[0019] Figure 12 is a schematic of a flow control system according to one
embodiment of the invention utilizing a fluid ratio control system, a fluid amplifier
system having a proportional amplifier in series with a bistable type amplifier, and a
pathway dependent resistance system;
[0020] Figures 3A and 13B are Computational Fluid Dynamic models showing
the flow patterns of fluid in the embodiment of the flow control system as seen in Figure
12;
[0021 ] Figure 14 is a perspective view of a flow control system according to the
present invention positioned in a tubular wail;
[0022] Figure 5 is a schematic of a flow control system according to one
embodiment of the invention designed to select a lower viscosity fluid over a higher
viscosity fluid;
[0023] Figure 16 is a schematic showing use of flow control systems of the
invention in an injection and a production well;
[0024] Figure 17A-C are schematic views of an embodiment of a pathway
dependent resistance systems of the invention, indicating varying flow rate over time;
Figure 18 is a chart of pressure versus flow rate and indicating the hysteresis effect
expected from the variance in flow rate ove time in the system of Figure 17;
[0025] Figure 19 is a schematic drawing showing a flow control system
according to one embodiment of the invention having a ratio control system, amplifier
system and pathway dependent resistance system, exemplary for use in inflow control
device replacement;
[0026] Figure 20 is a chart of pressure, P, versus flow rate, Q, showing the
behavior of the flow passageways in Figure 9 ;
[0027] Figure 2 1 is a schematic showing an embodiment of a flow control
system according to the invention having multiple valves in series, with an auxiliary flow
passageway and a secondary pathway dependent resistance system;
[0028] Figure 22 shows a schematic of a flow control system in accordance with
the invention for use in reverse cementing operations in a tubular extending into a
we bore;
[0029] Figure 23 shows a schematic of a flow control system in accordance with
the invention: and
[0030] Figure 24A-D shows schematic representational views of four alternate
embodiments of a pathway dependent resistance system of the invention.
[0031] It should be understood by those skilled in the art that the use of
directional terms such as above, below, upper, lower, upward, downward and the like are
used i relation to the illustrative embodiments as they are depicted in the figures, the
upward direction being toward the top of the corresponding figure and the downward
direction being toward the bottom of the corresponding figure. Where this is not the case
and a term is being used to indicate a required orientation, the Specification will state or
make such clear. Upstream and downstream are used to indicate location or direction in
relation to the surface, where upstream indicates relative position or movement towards
the surface along the weilbore and downstream indicates relative position or movement
further away from the surface along the weilbore.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0032] While the making and using of various embodiments of the present
invention are discussed in detail below, a practitioner of the art wi appreciate that the
present invention provides applicable inventive concepts which can be embodied in a
variety of specific contexts. The specific embodiments discussed herein are illustrative of
specific ways to make and use the invention and do not limit the scope of the present
invention.
[0033] Figure 1 is a schematic illustration of a well system, indicated generally
10, including a plurality of autonomous flow control systems embodying principles of the
present invention. A weilbore 12 extends through various earth strata. Weilbore 2 has a
substantially vertical section 14, the upper portion of which has installed therein a casing
string 16. Weilbore 2 also has a substantially deviated section 8, shown as horizontal,
which extends through a hydrocarbon-bearing subterranean formation 20. As illustrated,
substantially horizontal section 18 of weilbore 12 is open hole. While shown here in an
open hole, horizontal section of a wellbore, the invention will work in any orientation,
and in open or cased hole. The invention will also work equally well with injection
systems, as will be discussed supra.
[0034] Positioned within wellbore 12 and extending from the surface is a tubing
string 22. Tubing string 22 provides a conduit for fluids to travel from formation 20
upstream to the surface. Positioned within tubing string 22 in the various production
intervals adjacent to formation 20 are a plurality of autonomous flow control systems 25
and a plurality of production tubing sections 24 At either end of each production tubing
section 24 is a packer 26 that provides a fluid seal between tubing string 22 and the wa
of wellbore 12. The space in-between each pair of adjacent packers 26 defines a
production interval.
[0035] In the illustrated embodiment, each of the production tubing sections 24
includes sand control capability. Sand control screen elements or filter media associated
with production tubmg sections 24 are designed to allow fluids to flow therethrough but
prevent particulate matter of sufficient size from flowing therethrough. While the
invention does not need to have a sand control screen associated with it, if one is used,
then the exact design of the screen element associated with fluid flow control systems is
not critical to the present invention. There are many designs for sand control screens that
are well known in the industry, and will not be discussed here in detail. Also, a protective
outer shroud having a plurality of perforations therethrough may be positioned around the
exterior of any such filter medium.
[0036] Through use of the flow control systems 25 of the present invention in
one or more production intervals, some control over the volume and composition of the
produced fluids is enabled. For example, in an oil production operation if an undesired
fluid component, such as water, steam, carbon dioxide, or natural gas, is entering one of
the production intervals, the flow control system in that interval will autonomously
restrict or resist production of fluid from that interval.
[0037] The term ' natural gas" as used herein means a mixture of hydrocarbons
(and varying quantities of non-hydrocarbons) that exist in a gaseous phase at room
temperature and pressure. The term does not indicate that the natural gas is in a gaseous
phase at the dowtihole location of the inventive systems. ndeed it is to be understood
that the flow control system is for use in locations where the pressure and temperature are
such tha natural gas will be in a mostly liquefied state, though other components may be
present and some components may be in a gaseous state. The inventive concept will work
with liquids or gases or when both are present.
[0038] The fluid flowing into the production tubing section 24 typically
comprises more than one fluid component. Typical components are natural gas, oil,
water, steam or carbon dioxide. Steam and carbon dioxide are commonly used as
injection fluids to drive the hydrocarbon towards the production tubular, whereas natural
gas, oil and water are typically found in situ in the formation. The proportion of these
components in the fluid flowing into each production tubing section 24 will vary over
time and based on conditions within the formation and welibore. Likewise, the
composition of the fluid flowing into the various production tubing sections throughout
the length of the entire production string can vary significantly from section to section.
The flow control system is designed to reduce or restrict production from any particular
interval when it has a higher proportion of an undesired component.
[0039] Accordingly, when a production interval corresponding to a particularone
of the flow control systems produces a greater proportion of an undesired fluid
component, the flow control system in that interval will restrict or resist production flow
from that interval. Thus, the other production intervals which are producing a greater
proportion of desired fluid component, in this case oil, will contribute more to the
production stream entering tubing string 22. n particular, the flow rate from formation 20
to tubing string 22 will be less where the fluid must flow through a flow control system
(rather than simply flowing into the tubing string). Stated another way, the flow control
system creates a flow restriction on the fluid.
[0040] Though Figure 1 depicts one flow control system in each production
interval, it should be understood that any number of systems of the present invention can
be deployed within a production interval without departing from the principles of the
present invention. Likewise, th inventive flow control systems do not have to be
associated with every production interval. They may only be present in some of the
production intervals in the wellbore or may be in the tubing passageway to address
multiple production intervals.
[0041] Figure 2 is a side view in cross-section of a screen system 28, and an
embodiment of a flow control system 25 of the invention having a flow direction control
system, including a flow ratio control system 40, and a pathway dependent resistance
system 50. The production tubing section 24 has a screen system 28, an optional inflow
control device (not shown) and a flow control system 25. The production tubular defines
an interior passageway 32. Fluid flows from the formation 20 into the production tubing
section 24 through screen system 28. The specifics of the screen system are not explained
in detail here. Fluid, after being filtered by the screen system 28, if present, flows into the
interior passageway 32 of the production tubing section 24. As used here, the interior
passageway 32 of the production tubing section 24 can be an annular space, as shown, a
central cylindrical space, or other arrangement. In practice, downhole tools will have
passageways of various structures, often having fluid flow through annular passageways,
central openings, coiled or tortuous paths, and other arrangements for various puiposes.
The fluid may be directed through a tortuous passageway or other fluid passages to
provide further filtration, fluid control, pressure drops, etc. The fluid then flows into the
inflow control device, if present. Various inflow control devices are well known in the art
and are not described here in detail. An example of such a flow control device is
commercially available from Halliburton Energy Services, Inc. under the trade mark
EquiFlow®. Fluid then flows into the inlet 42 of the flow control system 25. While
suggested here that the additional inflow control device be positioned upstream from the
inventive device, it could also be positioned downstream of the inventive device or in
parallel with the inventive device.
[0042] Figure 3 is a schematic representational view of an autonomous flow
control system 25 of an embodiment of the invention. The system 25 has a fluid direction
control system 40 and a pathway dependent resistance system 50.
[0043] The fluid direction control system is designed to control the direction of
the fluid heading into one or more inlets of the subsequent subsystems, such as amplifiers
or pathway dependent resistance systems. The fluid ratio system is a preferred
embodiment of the fluid direction control system, and is designed to divide the fluid flow
into multiple streams of varying volumetric ratio by taking advantage of the characteristic
properties of the fluid flow. Such properties can include, but are not limited to, fluid
viscosity, fluid density, flow rates or combinations of the properties. When we use the
term "viscosity," we mean any of the rheologicai properties including kinematic
viscosity, yield strength, viscoplasticity, surface tension, wettability, etc. As the
proportional amounts of fluid components, for example oil and natural gas, in the
produced fluid change over time, the characteristic of the fluid flow also changes. When
the fluid contains a relatively high proportion of natural gas, for example, the density and
viscosity of the fluid will be less than for oil. The behavior of fluids in flow passageways
is dependent on the characteristics of the fluid flow. Further, certain configurations of
passageway will restrict flow, or provide greater resistance to flow, depending on the
characteristics of the fluid flow. The fluid ratio control system takes advantage of the
changes in fluid flow characteristics over the life of the well.
[0044] The fluid ratio system 40 receives fluid 2 1 from the interior passageway
32 of the production tubing section 24 or from the inflow control device through inlet 42.
The ratio control system 40 has a first passageway 44 and second passageway 46. As
fluid flows into the fluid ratio control system inlet 42, it is divided into two streams of
flow, one in the first passageway 44 and one in the second passageway 46. The two
passageways 44 and 46 are selected to be of different configuration to provide differing
resistance to fluid flow based on the characteristics of the fluid flow.
[0045] The first passageway 44 is designed to provide greater resistance to
desired fluids. In a preferred embodiment, the first passageway 44 is a long, relatively
narrow tube which provides greater resistance to fluids such as oil and less resistance to
fluids such as natural gas or water. Alternately, other designs for viscosity-dependent
resistance tubes can be employed, such as a tortuous path or a passageway with a textured
interior wall surface. Obviously, the resistance provided by the first passageway 44 varies
infinitely with changes in the fluid characteristic. For example, the first passageway will
offer greater resistance to the fluid when the oil to natural gas ratio o the fluid is
80:20 than when the ratio is 60:40. Further, the first passageway will offer relatively little
resistance to some fluids such as natural gas or water.
[0046] The second passageway 46 is designed to offer relatively constant
resistance to a fluid, regardless of the characteristics of the fluid flow, or to provide
greater resistance to undesired fluids. A preferred second passageway 46 includes at least
one flow restrictor 48. The flow restrictor 48 can be a venturi, an orifice, or a nozzle.
Multiple flow restrictors 48 are preferred. The number and type of restrictors and the
degree of restriction can be chosen to provide a selected resistance to fluid flow. The
first and second passageways may provide increased resistance to fluid flow as the fluid
becomes more viscous, but the resistance to flow in the first passageway will be greater
than the increase in resistance to flow in the second passageway.
[0047] Thus, the flow ratio control system 40 can be employed to divide the
fluid 2 1 into streams of a pre-selected flow ratio. Where the fluid has multiple fluid
components, the flow ratio will typically fall between the ratios for d e two single
components. Further, as the fluid formation changes in component constituency over
time, the flow ratio will also change. The change in the flow ratio is used to alter the fluid
flow pattern into the pathway dependent resistance system.
[0048] The flow control system 25 includes a pathway dependent resistance
system 50. In the preferred embodiment, the pathway dependent resistance system has a
first inlet 54 in fluid communication with the first passageway 44, a second inlet 56 in
fluid communication with the second passageway 46, a vortex chamber 52 and an outlet
58. The first inlet 54 directs fluid into the vortex chamber primarily tangentially. The
second inlet 56 directs fluid into the vortex chamber 56 primarily radially. Fluids entering
the vortex chamber 52 primarily tangentially will spiral around the vortex chamber before
eventually flowing through the vortex outlet 58. Fluid spiraling around the vortex
chamber will suffer from frictional losses. Further, the tangential velocity produces
ce t fugal force that impedes radial flow. Fluid from the second inlet enters the chamber
primarily radially and primarily flows down the vortex chamber wall and through the
outlet without spiral ing. Consequently, the pathway dependent resistance system provides
greater resistance to fluids entering the chamber primarily tangent ly than those
entering primarily radially. This resistance is realized as back-pressure on the upstream
fluid, and hence, a reduction in flow rate. Back-pressure can be applied to the fluid
selectively by increasing the proportion of fluid entering the vortex primarily
iangeniiaily, and hence the flow rate reduced, as is done in the inventive concept.
[0049] The differing resistance to flow between the first and second
passageways in the fluid ratio system results in a division of volumetric flow between the
two passageways. A ratio can be calculated from the two volumetric flow rates. Further,
the design of the passageways can be selected to result in particular volumetric flow
ratios. The fluid ratio system provides a mechanism for directing fluid which is relatively
less viscous into the vortex primarily tangentially, thereby producing greater resistance
and a lower flow rate to the relatively less viscous fluid than would otherwise be
produced.
[0050] Figures 4A and 4B are two Computational Fluid Dynamic models of the
flow control system of Figure 3 for flow patterns of both natural gas and oil. Model 4A
shows natural gas with approximately a 2 : volumetric flow ratio (flow rate through the
vortex tangential inlet 54 vs. vortex radial inlet 56) and model 4B shows oil with an
approximately 1:2 flow ratio. These models show that the with proper sizing and
selection of the passageways in the fluid ratio control system, the fluid composed of more
natural gas can be made to shift more of its total flow to take the more energy-wasting
route of entering the pathway dependent resistance system primarily tangentially. Hence,
the fluid ratio system can be utilized in conjunction with the pathway dependent
resistance system to reduce the amount of natural gas produced from any particular
production tubing section.
[0051] Note that in Figure 4 eddies 60 or "dead spots" can be created in the flow
patterns on the walls of the vortex chamber 52. Sand or particulate matter can settle out
of the fluid and build up at these eddy locations 60 Consequently, in one embodiment,
the pathway dependent resistance system further includes one or more secondary outlets
62 to allow the sa d to flush out of the vortex chamber 52 The secondary outlets 62 are
preferably in fluid communication with the production string 22 upstream from the vortex
chamber 52.
[0052] The angles at which the first and second i ets direct fluid into the vortex
chamber can be altered to provide for cases when the flow entering the pathway
dependent resistance system is closely balanced. The angles of the first and second inlets
are chosen such that the resultant vector combination of the first inlet flow and the second
inlet flow are aimed at the outlet 58 from the vortex chamber 52. Alternatively, the angles
of the first and second inlet could be chosen such that the resultant vector combination of
the first and second inlet flow will maximize the spiral of the fluid flow in the chamber.
Alternately, the angles of the first and second inlet flow could be chosen to minimize the
eddies 60 in the vortex chamber. The practitioner will recognize that the angles of the
inlets at their connection with the vortex chamber can be altered to provide a desired flow
pattern in the vortex chamber.
[0053] Further, the vortex chamber can include flow vanes or other directional
devices, such as grooves, ridges, "waves" or other surface shaping, to direct fluid flow
within the chamber or to provide additional flow resistance to certain directions of
rotation. The vortex chamber can be cylindrical, as shown, or right rectangular, oval,
spherical, spheroid or other shape.
[0054] Figure 5 is a schematic of an embodiment of a flow control system 5
having a fluid ratio system 40, pathway dependent resistance system 1 0 and fluid
amplifier system 70. In a preferred embodiment, the flow control system 125 has a fluid
amplifier system 70 to amplify the ratio split produced in the first and second
passageways 144, 146 of the ratio control system 4 0 such that a greater ratio is achieved
in the volumetric flow in the first inlet 54 and second inlet 156 of the pathway
dependent resistance system 1 0 . In a preferred embodiment, the fluid ratio system 1 0
further includes a primary flow passageway 147. In this embodiment, the fluid flow is
split into three flow paths along the flow passageways 144, 46 and 47 with the primary
flow in the primary passageway 147. It is to be understood that the division of flows
among the passageways can be selected by the design parameters of the passageways.
The primary passageway 1 7 is not necessary for use of a fluid amplifier system, but is
preferred. As an example of the ratio of inlet flows between the tliree inlets, the flow ratio
for a fluid composed primarily of natural gas may be 3:2:5 for the first: second :primary
passageways. The ratio for fluid primarily composed of oil may be 2:3:5.
[0055] The fluid amplifier system 170 has a first inlet 74 in fluid
communication with the first passageway 144, a second inlet 176 in fluid communication
with the second passageway 6 and a primary inlet 177 in fluid communication with
primary passageway 147. The inlets 174, 76 and 177 of the fluid amplifier system 70
join together at amplifier chamber 180. Fluid flow into the chamber 0 is then divided
into amplifier outlet 4 which is in fluid communication with pathway dependent
resistance system inlet 154, and amplifier outlet 1 6 which is in fluid communication
with pathway dependent resistance system inlet 56. The amplifier system 170 is a fluid ic
amplifier which uses relatively low-value input flows to control higher output flows. The
fluid entering the amplifier system 70 becomes a stream forced to flow in selected ratios
into the outlet paths by careful design of the internal shapes of the amplifier system 370.
The input passageways 144 and 146 of the fluid ratio system act as controls, supplying
jets of fluid which direct the flow from the primary passageway 347 into a selected
amplifier outlet 1 4 or 186. The control jet flow can be of far lower power than the flow
of the primary passageway stream, although this is not necessary. The amplifier control
inlets 74 and 6 are positioned to affect the resulting flow stream, thereby controlling
the output through outlets 4 and 186.
[0056] The internal shape of the amplifier inlets can be selected to provide a
desired effectiveness in determining the flow pattern through the outlets. For example,
the amplifier inlets 74 and 176 are illustrated as connecting at right angles to the
primary inlet 77. Angles of connection can be selected as desired to control the fluid
stream. Further, the amplifier inlets 174, 76 and 77 are each shown as having nozzle
restrictions 87, 88 and 89, respectively. These restrictions provide a greater jetting
effect as the flow through the inlets merges a chamber 0 The chamber 1 0 can also
have various designs, including selecting the sizes of the inlets, the angles at which the
inlets and outlets attach to the chamber, the shape of the chamber, such as to minimize
eddies and flow separation, and the size and angles of the outlets. Persons of skill in the
art will recognize that Figure 5 is but one example embodiment of a fluid amplifier
system and that other arrangements can be employed. Further, the number and type of
fluid amplifier can be selected.
[0057] Figures 6A and 6B are two Computational Fluid Dynamic models
showing the flow ratio amplification effects of a fluid amplifier system 270 in a flow
control system in an embodiment of the invention. Model 6A shows the flow paths when
the only fluid component is natural gas. The volumetric flow ratio between the first
passageway 244 and second passageway 246 is 30:20, with fifty percent of the total flow
in the primary passageway 247. The fluid amplifier system 270 acts to amplify this ratio
to 98:2 between the first amplifier outlet 284 and second outlet 286. Similarly, model 6B
shows an amplification of flow ratio fro 20:30 (with fifty percent of the total flow
through the primary passageway) to 19:8 where the sole fluid component is oil.
[0058] The fluid amplifier system 170 illustrated in Figure 5 is a jet-type
amplifier; that is, the amplifier uses the jet effect of the incoming streams from the inlets
to alter and direct the path of flow through the outlets. Other types of amplifier systems,
such as a pressure-type fluid amplifier, are shown in Figure 7 . The pressure-type
amplifier system 370 of Figure 7 is a fluidic am ifier which uses relatively low-value
input pressures to control higher output pressures; that is, fluid pressure acts as the
control mechanism for directing the fluid stream. The first amplifier inlet 374 and second
inlet 376 each have a venturi nozzle restriction 390 and 3 1, respectively, which acts to
increase fluid speed and thereby to reduce fluid pressure in the inlet passageway. Fluid
pressure communication ports 392 and 393 convey the pressure difference between the
first and second inlets 374 and 376 to the primary inlet 377. The fluid flow in the
primary inlet 377 will be biased toward the low pressure side and away from the high
pressure s de For example, where the fluid has a relatively larger proportion of natural
gas component, the fluid volumetric flow ratio will be weighted towards the first
passageway of the fluid ratio system and first inlet 374 of the amp fi er system 370. The
greater flow rate in the first inlet 374 will result in a lower pressure transmitted through
pressure port 390, while the lesser flow rate in the second inlet 376 will result in a higher
pressure communicated through port 393. The higher pressure w l "push," or the lower
pressure will "suction," the pri mar ' fluid flow through the primary inlet 377 resulting in
a greater proportion of flow through amplifier outlet 354. Note that the outlets 4 and
356 in this embodiment are in different positions than the outlets in the jet-type amplifier
system of Figure 5.
[0059] Figure 8 is a perspective view (with "hidden" lines displayed) of a flow
control system of a preferred embodiment in a production tubular. The flow control
system 425, in a preferred embodiment, is milled, cast, or otherwise formed "into" the
wall of a tubular. The passageways 444, 446, 447, inlets 474, 476, 477, 454, 456,
chambers such as vortex chamber 452, and outlets 484, 486 of the ratio control system
440 fluid amplifier syste 470 and pathway dependent resistance system 450 are, at
least in part, defined by the shape of exterior surface 429 of the tubular wall 427. A
sleeve is t en place over the exterior surface 429 of the wail 427 and portions of the
interior surface of the sleeve 433 define, at least in part, the various passageways and
chambers of d e system 425. Alternately, the milling may be on the interior surface of the
sleeve with the sleeve positioned to cover the exterior surface of the tubular wall. In
practice, it may be preferred that the tubular wall and sleeve define only selected
elements of the flow control system. For example, the pathway dependent resistance
system and amplifier system may be defined by the tubular wall while the ratio control
system passageways are not. In a preferred embodiment, the first passageway of the fluid
ratio control system, because of its relative length, is wrapped or coiled around the
tubular. The wrapped passageway can be positioned within, on the exterior or interior of
the tubular wall. Since the length of the second passageway of the ratio control system is
typical y not required to be of the same length as the first passageway, the second
passageway may not require wrapping, coiling, etc.
[0060] Multiple flow control systems 525 can be used in a single tubular. For
example. Figure 9 shows multiple flow control systems 525 arranged in the tubular wall
53 1 of a single tubular. Each flow control system 525 receives fluid input from an interior
passageway 532 of the production tubing section. The production tubular section may
have one or multiple interior passageways for supplying fluid to the flow control systems.
In one embodiment, the production tubular has an annular space for fluid flow, which can
be a single annular passageway or divided into multiple passageways spaced about the
annulus. Alternately, the tubular can have a single central interior passageway from
which fluid flows into one or more flow control systems. Other arrangements will be
apparent to those skilled in the art.
(0061 ] Figure 10 is a schematic of a flow control system having a fluid ratio
system 640, a fluid amplifier system 670 which utilizes a pressure-type amplifier with a
bistable switch, and a pathway dependent resistance system 650 The flow control
system as seen in Figure 10 is designed to select oil flow over gas flow. That is, the
system creates a greater back-pressure when the formation fluid is less viscous, such as
when it is comprised of a relatively higher amount of gas, by directing most of the
formation fluid nto the vortex primarily tangentially. When the formation fluid is more
viscous, such as when it comprises a relatively larger amount of oil, then most of the fluid
is directed into the vortex primarily radially and little back-pressure is created. The
pathway dependent resistance system 650 is downstream from the amplifier 670 which,
in turn, is downstream from the fluid ratio control system 640. As used with respect to
various embodiments of the fluid selector device herein, "downstream" shall mean in the
direction of fluid flow while in use or further along in the direction of such flow.
Similarly, "upstream" shall mean the opposite direction. Note that these terms may be
used to describe relative position in a wellbore, meaning further or closer to the surface,
such use should be obvious from context.
[0062] The fluid ratio system 640 is again shown with a first passageway 644
and a second passageway 646. The first passageway 644 is a viscosity-dependent
passageway and will provide greater resistance to a fluid of higher viscosity. The first
passageway can be a relatively long, narrow tubular passageway as shown a tortuous
passageway or other design providing requisite resistance to viscous fluids. For example,
a laminar pathway can be used as a viscosity-dependent fluid flow pathway. A laminar
pathway forces fluid flow across a relatively large surface area in a relatively thin layer,
causing a decrease in velocity to make the fluid flow laminar. Alternately, a series of
differing sized pathways can function as a viscosity-dependent pathway. Further, a
swellable material can be used to define a pathway, wherein the material swells in the
presence of a specific fluid, thereby shrinking the fluid pathway. Further, a material with
different surface energy, such as a hydrophobic, hydrophilic, water-wet, or oil-wet
material, can be used to define a pathway, wherein the wettability of the material restricts
flow.
[0063] The second passageway 646 is less viscosity dependent, that is, fluids
behave relatively similarly flowing through the second passageway regardless of their
relative viscosities. The second passageway 646 is shown having a vortex diode 649
through which the fluid flows. The vortex diode 649 can be used as an alternative for the
nozzle passageway 646 as explained herein, such as with respect to Figure 3, for
example. Further, a swellable material or a material with special wettability can be used
to define a pathway.
[0064] Fluid flows from the ratio control system 640 into the fluid amplifier
system 670. The first passageway 644 of the fluid ratio system is in fluid cornmunication
with the first inlet 674 of the amplifier system. Fluid in the second passageway 646 of
the fluid ratio system flows into the second inlet 676 of the amplifier system. Fluid flow
in the first and second inlets combines or merges into a single flow path in primary
passageway 680 The amplifier system 670 includes a pressure-type fluid amplifier 671
similar to the embodiment described above with regard to Figure 7. The differing flow
rates of the fluids in the first and second inlet create differing pressures. Pressure drops
are created the first and second inlets at the junctions with the pressure communication
ports. For example, and as explained above, venturi nozzles 690 and 691 , can be utilized
at or near the junctions. Pressure communication ports 692 and 693 communicate the
fluid pressure from the inlets 674 and 676, respectively, to the jet of fluid in primaiy
passageway 680. The low pressure communication port, that is, the port connected to the
inlet with the higher flow rate, will create a low-pressure "suction" which will direct the
fluid as it jets through the primaiy passageway 680 past the downstream ends of the
pressure communication ports.
[0065] in the embodiment seen at Figure 0, the fluid flow through inlets 674
and 676 merges into a single flow-path prior to being acted upon by the pressure
communication ports. The alternative arrangement in Figure 7 shows the pressure ports
directing flow of the primary inlet 377, with the flow in the primary inlet split into two
flow streams in first and second outlets 384 and 386. The flow through the first inlet 374
merges with flow through second outlet 386 downstream of the pressure communication
ports 392 and 393 Similarly, flow in second inlet 376 merges with flow in first outlet
384 downstream from the communication ports. In Figure 10, a l of the fluid flow
through the fluid amplifier system 670 is merged together in a single jet at primaiy
passageway 680 prior to, or upstream of, the communication ports 692 and 693. Thus the
pressure ports act on the combined stream of fluid flow.
[0066] The amplifier system 670 also includes, in this embodiment, a bistable
switch 673, and first and second outlets 684 and 686. Fluid moving through primaiy
passageway 680 is split into two fluid streams in first and second outlets 684 and 686.
The flow of the fluid from the primary passageway is directed into the outlets by the
effect of the pressure communicated by the pressure communication ports, with a
resulting fluid flow split into the outlets. The fluid split between the outlets 684 and 686
defines a fluid ratio; the same ratio is defined by the fluid volumetric flow rates through
the pathway dependent resistance system inlets 654 and 656 n this embodiment. This
fluid ratio is an amplified ratio over the ratio between flow through inlets 674 and 676.
[0067] The flow control system in Figure 10 includes a pathway dependent
resistance system 650. The pathway dependent resistance system has a first inlet 654 in
fluid communication with the first outlet 684 of the fluid amplifier system 644, a second
inlet 656 in fluid communication with the second passageway 646, a vorte chamber 52
and an outlet 658. The first inlet 654 directs fluid into the vortex chamber primarily
tangentially. The second inlet 656 directs fluid into the vortex chamber 656 primarily
radially. Fluid entering the vortex chamber 652 primarily tangentially will spiral around
the vortex wail before eventually flowing through the vortex outlet 658. Fluid spiraling
around the vortex chamber increases in speed with a coincident increase in frictional
losses The tangential velocity produces centrifugal force that impedes radial flow. Fluid
from the second inlet enters the chamber primarily radially and primarily flows down the
vortex chamber wall and through the outlet without spiraling. Consequently, the pathway
dependent resistance system provides greater resistance to fluids entering the chamber
primarily tangentially than those entering primarily radially. This resistance is realized as
back-pressure on the upstream fluid. Back-pressure can be applied to the fluid selectively
where the proportion of fluid entering the vortex primarily tangentially is controlled
[0068] The pathway dependent resistance system 650 functions to provide
resistance to the fluid flow and a resulting back-pressure on the fluid upstream. The
resistance provided to the fluid flow is dependent upon and in response to the fluid flow
pattern imparted to the fluid by the fluid ratio system and, consequently, responsive to
changes in fluid viscosity. The fluid ratio system selectively directs the fluid flow into
the pathway dependent resistance system based on the relative viscosity of the fluid over
time. The pattern of fluid flow into the pathway dependent resistance system determines,
at least in part, the resistance imparted to the fluid flow by the pathway dependent
resistance system. Elsewhere herein is described pathway dependent resistance system
use based on the relative flow rate over time. The pathway dependent resistance system
can possibly be of other design, but a system providing resistance to the fluid flow
through centripetal force is preferred.
[0069] Note that in this embodiment, the fluid amplifier system outlets 684 and
686 are on opposite "sides" of the system when compared to the outlets in Figure 5. That
is, in Figure 10 the first passageway of the fluid ratio system, the first inlet of the
amplifier system and the first inlet of the pathway dependent resistance system are all on
the same longitudinal s de of the flow control system. This is due to the use of a
pressure-type amplifier 671 ; where a jet-type amplifier is utilized, as in Figure 5, the first
fluid ratio control system passageway and first vortex inlet will be on opposite sides of
the system. The relative positioning of passageways and inlets will depend on the type
and number of amplifiers employed. The critical design element is that the amplified
fluid flow be directed into the appropriate vortex inlet to provide radial or tangential flow
in the vortex.
[0070] The embodiment of the flow control system shown in Figure 1 can also
be modified to utilize a primary passageway in the fluid ratio system, and p mary inlet in
the amplifier system, as explained with respect to Figure 5 above.
[0071] Figures l A-B are Computational Fluid Dynamic models showing test
results of flowing fluid of differing viscosities through the flow system as seen in Figure
10. The tested system utilized a viscosity-dependent first passageway 644 having an ID
with a cross-section of 0.04 square inches. The viscosity-independent passageway 646
utilized a 1.4 inch diameter vortex diode 649. A pressure-type fluid amplifier 671 was
employed, as shown and as explained above. The bistable switch 673 used was 3 inches
long with 0.6 inch passageways. The pathway dependent resistance system 650 had a 3
inch diameter chamber with a 0.5 inch outlet port.
[0072] Figure A shows a Computational Fluid Dynamic model of the system
in which oil having a viscosity of 25 cP is tested. The fluid flow ratio defined by
volumetric fluid flow rate through the first and second passageways of the flow ratio
control system was measured as 47:53. In the pressure-type amplifier 6 1 the flow rates
were measured as 88.4% through primary passageway 680 and 6.6% and 5% through the
first and second pressure ports 692 and 693, respectively. The fluid ratio induced by the
fluid amplifier system, as defined by the flow rates through the first and second amplifier
outlets 684 and 686, was measured as 70 30 The bistable switch or the selector system,
with this flow regime, is said to be "open."
[0073] Figure MB shows a Computational Fluid Dynamic model of the same
system utilizing natural gas having a viscosity of 0.022 cP The Computational Fluid
Dynamic model is for gas under approximately 5000 psi. The fluid flow ratio defined by
volumetric fluid flow rate through the first and second passageways of the flow ratio
control system was measured as 55:45. In the pressure-type amplifier 671 the flow rates
were measured as 92.6% through primary passageway 680 and 2 8% and 4.6% through
the first and second pressure ports 692 and 693, respectively. The fluid ratio induced by
the fluid amplifier system, as defined by the flow rates through the first and second
amplifier outlets 684 and 686, was measured as 0:90 The bistable switch or the selector
system, with this flow regime, is said to be "closed" since the majority of fluid is directed
through the first vortex inlet 654 and enters the vortex chamber 652 primarily
tangentiaily, as can be seen by the flow patterns in the vortex chamber, creating relatively
high back-pressure on the fluid
[0074] In practice, it may be desirable to utilize multiple fluid amplifiers in
series i the fluid amplifier system. The use of multiple amplifiers will allow greater
differentiation between fluids of relatively similar viscosity; that is, the system wi l better
be able to create a different flow pattern through the system when the fluid changes
relatively little in overall viscosity. A plurality of amplifiers in series will provide a
greater amplification of the fluid ratio created by the fluid ratio control device.
Additionally, the use of multiple amplifiers will help overcome the inherent stability of
any bistable switch in the system, allowing a change in the switch condition based on a
smaller percent change of fluid ratio in the fluid ratio control system.
[0075] Figure 12 is a schematic of a flow control system according to one
embodiment of the invention utilizing a fluid ratio control system 740, a fluid amplifier
system 770 having two amplifiers 790 and 795 in series, and a pathway dependent
resistance system 750. The embodiment in Figure 12 is similar to the flow control
systems described herein and will be addressed only briefly. From upstream to
downstream, the system is arranged with the flow ratio control system 740, the fluid
amplifier system 770 the bi-stable amplifier system 795, and the patliway dependent
resistance system 750.
[0076] The fluid ratio system 740 is shown having first second and primary
passageways 744, 746, and 747. In this case, both the second 46 and primary
passageways 747 utilize vortex diodes 749. The use of vortex diodes and other control
devices is selected based on design considerations including the expected relative
viscosities of the fluid over time, the preselected or target viscosity at which the fluid
selector is to "select" or allow fluid flow relatively unimpeded through the system, the
characteristics of the environment in which the system is to be used, and design
considerations such as space, cost, ease of system, etc. Here, the vortex diode 749 in the
primary passageway 747 has a larger outlet than that of the vortex diode in the second
passageway 746. The vortex diode is included in the primary passageway 747 to create a
more desirable ratio split, especially when the formation fluid is comprised of a larger
percentage of natural gas. For example based on testing, with or without a vortex diode
749 in the primary passageway 747, a typical ratio split (first; second: primary) through
the passageways when the fluid is composed primarily of oil was about 29:38:33. When
the test fluid was primarily composed of natural gas and no vortex diode was utilized in
the primary passageway, the ratio split was 35:32:33. Adding the vortex diode to the
primary passageway, that ratio was altered to 38:33:29 Preferably, the ratio control
system creates a relatively larger ratio between the viscosity-dependent and independent
passageways (or vice versa depending on whether the user wants to select production for
higher or lower viscosity fluid). Use of the vortex diode assists in creating a larger ratio.
While the difference in using the vortex diode may be relatively small, it enhances the
performance and effectiveness of the amplifier system.
[0077] Note that in this embodiment a vortex diode 749 is utilized in the
"viscosity independent" passageway 746 rather than a multiple orifice passageway. As
explained herein, different embodiments may be employed to create passageways which
are relatively dependent or independent dependent on viscosity. Use of a vortex diode
749 creates a lower pressure drop for a fluid such as oil, which is desirable in some
utilizations of the device. Further, use of selected viscosity-dependent fluid control
devices (vortex diode, orifices, etc.) may improve the fluid ratio between passageways
depending on the application.
[0078] The fluid amplifier system 770 in the embodiment shown in Figure 12
includes two fluid amplifiers 790 and 795. The amplifiers are arranged in series. The
first amplifier is a proportional amplifier 790. The first amplifier system 790 has a first
inlet 774, second inlet 776, and primary inlet 777 in fluid communication with,
respectively, the first passageway 746, second passageway 746 and primary passageway
747 of the fluid ratio control system. The first, second and primary inlets are connected
to one another and merge the fluid flow through the inlets as described elsewhere herein.
The fluid flow is joined into a single fluid flow stream at proportional amplifier chamber
780. The flow rates of fluid from the first and second inlets direct the combined fluid
flow into the first outlet 784 and second outlet 786 of the proportional amplifier 790. The
proportional amplifier system 790 has two "lobes" for handling eddy flow and minor
flow disruption. A pressure-balancing port 789 fluidiy connects th two lobes for
balancing pressure between the two lobes on either side of the amplifier.
[0079] The fluid amplifier system further includes a second fluid amplifier
system 795, in this case a bistable switch amplifier. The amplifier 795 has a first inlet
794, a second inlet 796 and a primary inlet 797. The first and second inlets 794 and 796
are, respectively, in fluid communication with first and second outlets 784 and 786. The
bistable switch amplifier 795 is shown having a primary inlet 797 which is in fluid
communication with the interior passageway of the tubular. The fluid flow from the first
and second inlets 794 and 796 direct the combined fluid flows from the inlets into the
first and second outlets 798 and 799. The pathway dependent resistance system 750 is as
described elsewhere herein.
[0080] Multiple amplifiers can be employed in series to enhance the ratio
division of the fluid flow rates. In the embodiment shown, for example, where a fluid
composed primarily of oil is flowing through the selector system, the fluid ratio system
740 creates a flow ratio between the first and second passageways of 29:38 (with the
remaining 33 percent of flow through the pri ar ' passageway). The proportional
amplifier system 790 may amplify the ratio to approximately 20:80 (first:second outlets
of amplifier system 790) The bistable switch amplifier system 795 may then amplify the
ratio further to, say, 10:90 as the fluid enters the first and second inlets to the pathway
dependent resistance system. n practice, a bistable amplifier tends to be fairly stable.
That s, switching the flow partem in the outlets of the bistable switch may require a
relatively large change in flow pattern in the inlets. The proportional amplifier tends to
divide the flow ratio more evenly based on the inlet flows. Use of a proportional
amplifier, such as at 790, will assist in creating a large enough change in flow pattern into
the bistable switch to effect a change in the switch condition (from "open" to "closed and
vice versa).
(0081 ] The use of multiple amplifiers in a single amplifier system can include
the use of any type or design of amplifier known in the art, including pressure-type, jettyp
e bistable proportional amplifiers, etc., in any combination. It is specifically taught
that the amplifier system can utilize any number and type of fluid amplifi er in series or
parallel. Additionally, the amplifier systems can include the use of primary inlets or not,
as desired. Further, as shown, the primary inlets can be fed with fluid directly from the
interior passageway of the tubular or other fluid source. The system in Figure 12 is
shown "doubling-back" on itself; tha is, reversing the direction of flow from left to right
across the system to right to left. This is a space-saving technique but is not critical to the
invention. The specifics of the relative spatial positions of the fluid ratio system,
amplifier system and pathway dependent resistance system will be informed by design
considerations such as available space, sizing, materials, system and manufacturing
concerns.
[0082] Figures 13A and 13B are Computational Fluid Dynamic models showing
the flow patterns of fluid in the embodiment of the flow control system as seen in Figure
12. In Figure 3A, the fluid utilized was natural gas. The fluid ratio at the first, second
and primary fluid ratio system outlets was 38:33:29. The proportional amplifier system
790 amplified th ratio to approximately 60:40 in the first and second outlets 784 and
786. That ratio was further amplified by the second amplifier system 795, where the
first:second:primary inlet ratio was approximately 40:30:20 The output ratio of the
second amplifier 795 as measured at either the first and second outlets 798 and 799 or at
the first and second inlets to the pathway dependent resistance system was approximately
99: . The fluid of relatively low viscosity was forced to flow primarily into the first inlet
of the pathway dependent resistance system and then into the vortex at a substantially
tangential path. The fluid is forced to substantially rotate about the vortex creating a
greater pressure drop than if the fluid had entered the vortex primarily radially. This
pressure drop creates a back-pressure on the fluid in the selector system and slows
production of fluid.
[0083] In Figure 13B, a Computational Fluid Dynamic model is shown wherein
the tested fluid was composed of oi of viscosity 25 cP. The fluid ratio control system
740 divided the flow rate into a ratio of 29:38:33. The first amplifier system 790
amplified the ratio to approximately 40:60 The second amplifier system 795 further
amplified that ratio to approximately 10:90. As can be seen, the fluid was forced to flow
into the pathway dependent resistance system primarily through the second substantially
radial inlet 56. Although some rotational flow is created in the vortex, the substantial
portion of flow is radial. This flow pattern creates less of a pressure drop on the oil than
would be created if the oil flowed primarily tangentially into the vortex. Consequently,
less back-pressure is created on the fluid in the system. The flow control system is said
to "select the higher viscosity fluid, oil in this case, over the less viscous fluid, gas.
[0084] Figure 14 is a perspective, cross-sectional view of a flow control system
according to the present invention as seen in Figure 2 positioned in a tubular wall. The
various portions of the flow control system 25 are created in the tubular wall 73 . A
sleeve, not shown, or other covering is then placed over the system. The sleeve, n this
example, forms a portion of the walls of the various fluid passageways. The passageways
and vortices can be created by milling, casting or other method. Additionally, the various
portions of the flow control system can be manufactured separately and connected
together.
[0085] The examples and testing results described above in relation to Figures
10-14 are designed to select a more viscous fluid, such as oil, over a fluid with different
characteristics, such as natural gas. That is, the flow control system allows relatively
easier production of the fluid when it is composed of a greater proportion of oil and
provides greater restriction to production of the fluid when it changes in composition
over time to having a higher proportion of natural gas. Note that the relative proportion
of oil is not necessarily required to be greater than half to be the selected fluid. It s to be
expressly understood that the systems described can be utilized to select between any
fluids of differing characteristics. Further, the system can be designed to select between
the formation fluid as it varies between proportional amounts of any fluids. For example,
in an oil well where the fluid flowing from the formation is expected to vary over time
between ten and twenty percent oil composition, the system can be designed to select the
fluid and allow relatively greater flow when the fluid is composed of twenty percent oil.
[0086] In a preferred embodiment, the system can be used to select the fluid
when it has a relatively lower viscosity over when it is of a relatively higher viscosity.
That is, the system can select to produce gas over oil, or gas over water. Such an
arrangement is useful to restrict production of oil or water in a gas production well. Such
a design change can be achieved by altering the pathway dependent resistance system
such that the lower viscosity fluid is directed into the vortex primarily radially while the
higher viscosity fluid is directed into the pathway dependent resistance system primarily
tangentiaSly. Such a system is shown at Figure 15 .
[0087] Figure 5 is a schematic of a flow control system according to one
embodiment of the invention designed to select a lower viscosity fluid over a higher
viscosity fluid. Figure 1 is substantially similar to Figure 1 and will not be explained
in detail. Note that the inlets 854 and 856 to the vortex chamber 852 are modified, or
"reversed," such that the inlet 854 directs fluid into the vortex 852 primarily radially
while the inlet 856 directs fluid into the vortex chamber primarily tangentially. Thus,
when the fluid is of relatively low viscosity, such as when composed primarily of natural
gas, the fluid is directed into the vortex primarily radially The fluid is "selected," the
flow control system is "open," a low resistance and back-pressure is imparted on the
fluid, and the fluid flows relatively easily thiough the system. Conversely, when the fluid
is of relatively higher viscosity, such as when composed of a higher percentage of water,
it is directed into the vortex primarily tangentially. The higher viscosity fluid is not
selected, the system is "closed," a higher resistance and back-pressure (than would be
imparted without the system in place) is imparted to the fluid, and the production of the
fluid is reduced. The flow control system can be designed to switch between open and
closed at a preselected viscosity or percentage composition of fluid components. For
example, the system may be designed to close when the fluid reaches 40% water (or a
viscosity equal to that of a fluid of that composition). The system can be used in
production, such as in gas wells to prevent water or oil production, or in injection systems
for selecting injection of steam over water. Other uses will be evident to those skilled in
the art, including using other characteristics of the fluid, such as density or flow rate
[0088] The flow control system can be used in other methods, as well. For
example, in oilfield work-over and production it is often desired to inject a fluid, typically
steam, into an injection well
[0089] Figure 16 is a schematic showing use of the flow control system of the
invention in an injection and a production well. One or more injection wells 1200 are
injected with an injection fluid while desired formation fluids are produced at one or
more production well 1300. The production well 1300 wellbore 1302 extends through
the formation 204. A tubing production string 1308 extends through the wellbore
having a plurality of production tubular sections 24 The production tubular sections 24
can be isolated from one another as described n relation to Figure 1 by packers 26.
Flow control systems can be employed on either or both of the injection and production
wells.
[0090] Injection well 1200 includes a wellbore 1202 extending through a
hydrocarbon bearing formation 1204. The injection apparatus includes one or more
steam supply lines 206 which typically extend fro the surface to the downhole location
of injection on a tubing string 1208. Injection methods are known in the art and will not
be described here i detail. Multiple injection port systems 1210 are spaced along the
length of the tubing string 1208 along the target zones of the formation. Each of the port
systems 1210 includes one or more autonomous flow control systems 1225. The flow
control systems can be of any particular arrangement discussed herein, for example, of
d e design shown at Figure 15, shown in a preferred embodiment for injection use.
During the injection process, hot water and steam are often commingled and exist in
varying ratios in the injection fluid. Often hot water is circulated downhole until the
system has reached the desired temperature and pressure conditions to provide primarily
steam for injection into the formation. It is typically not desirable to inject hot water into
the formation
009 Consequently, the flow control systems 225 are utilized to select for
injection of steam (or other injection fluid) over injection of hot water or other less
desirable fluids. The fluid ratio system will divide the injection fluid into flow ratios
based on a relative characteristic of the fluid flow, such as viscosity, as it changes over
time. When the injection fluid has an undesirable proportion of water and a consequently
relatively higher viscosity, the ratio control system will divide d e flow accordingly and
the selector system will direct the fluid into the tangential inlet of the vortex thereby
restricting injection of water into the formation. As the injection fluid changes to a
higher proportion of steam, with a consequent change to a lower viscosity, the selector
system directs the fluid into the pathway dependent resistance system primarily radially
allowing injection of the steam with less back-pressure than if the fluid entered the
pathway dependent resistance system primarily tangentially. The fluid ratio control
system 40 can divide the injection fluid based on any characteristic of the fluid flow,
including viscosity, density, and velocity.
[0092] Additionally, flow control systems 25 can be utilized on the production
well 1300. The use of the selector systems 25 in the production well can be understood
through e explanation herein, especially with reference to Figure 1 and 2. As steam is
forced through the formation 1204 from the injection well 200 the resident
hydrocarbon, for example o i l, in the formation is forced to flow towards and into the
production well 1300. Flow control systems 25 on the production well 1300 wil l select
for the desired production fluid and restrict the production of injection fluid. When the
injection fluid "breaks through" and begins to be produced in the production wel l , the
flow control systems will restrict production of the injection fluid. It is typical that the
injection fluid will break-through along sections of the production wellbore unevenly.
Since the flow control systems are positioned along isolated production tubing sections,
the flow control systems will allow for less restricted production of formation fluid in the
production tubing sections where break-through has not occurred and restrict production
of injection fluid from sections where break-through has occurred. Note that the fluid
flow from each production tubing section is connected to the production string 302 In
parallel to provide for such selection.
[ 93 The injection methods described above are described for steam injection.
It is to be understood that carbon dioxide or other injection fluid can be utilized. The
selector system will operate to restrict the flow of the undesired injection fluid, such as
water, while not providing increased resistance to flow of desired injection fluid, such as
steam or carbon dioxide. In its most basic design, the flow control system for use in
injection methods is reversed in operation from the fluid flow control as explained herein
for use in production. That is, the injection fluid flows from the supply lines, through the
flow control system (flow ratio control system, amplifier system and pathway dependent
resistance system), and then into the formation. The flow control system is designed to
select the preferred injection fluid; that is, to direct the injection fl id into the pathway
dependent resistance system primarily radially. The undesired fluid, such as water, is not
selected; that is, it is directed into the pathway dependent resistance system primarily
tangentiaily. Thus, when the undesired fluid is present in the system, a greater backpressure
is created on the fluid and fluid flow is restricted. Note that a higher back
pressure is imparted on the fluid entering primarily tangentiaily than would be imparted
were the selector system not utilized. This does not require that the back-pressure
necessarily be higher on a non-selected fluid than on a selected fluid, although that may
we be preferred.
[0094] A bistable switch, such as shown at switch 170 in Figure 5 and at switch
795 in Figure 12, has properties which can be utilized for flow control even without the
use of a flow ratio system. Bistable switch 795 performance is flow rate, or velocity,
dependent. That is, at low velocities or flow rates the switch 795 lacks bistabiiity and
fluid flows into the outlets 798 and 799 in approximately equal amounts. As the rate of
flow into the bistable switch 795 increases, bistabiiity eventually forms.
[0095] At least one bistable switch can be utilized to provide selective fluid
production in response to fluid velocity or flow rate variation. In such a system, fluid is
"selected" or the fluid control system is open where the fluid flow rate is under a
preselected rate. The fluid at a low rate will flow through the system with relatively little
resistance. When the flow rate increases above the preselected rate, the switch is
"flipped" closed and fluid flow is resisted. The closed valve will, of course, reduce the
flow rate through the system A bistable switch 0, as seen in Figure 5, once activated,
will provide a Coanda effect on the fluid stream. The Coanda effect is the tendency of a
fluid jet to be attracted to a nearby surface. The term is used to describe the tendency of
the fluid jet exiting the flow ratio system, once directed into a selected switch outlet, such
as outlet 184, to stay directed in that flow path even where the flow ratio returns to its
previous condition due to the proximity of the fluid switch wall. At a low flow rate, the
bistable switch lacks bistabiiity and the fluid flows approximately equally through the
outlets 184 and 186 and then about equally into the vortex inlets 154 and 156.
Consequently, little back-pressure is created on the fluid and the flow control system is
effectively open. As the rate of flow into the bistable switch 170 increases, bistabiiity
eventually forms and the switch performs as intended, directing a majority of the fluid
flow through outlet 84 and then primarily tangentially into the vortex 152 through inlet
154 thereby closing the valve. The back-pressure, of course, will result in reduced flow
rate, but the Coanda effect will maintain the fluid flow into switch outlet 84 even as the
flow rate drops. Eventually, the flow rate may drop enough to overcome the Coanda
effect and flow will return to approximately equal flow through the switch outlets,
thereby re-opening the valve
[0096] The velocity or flow rate dependent flow control system can utilize fluid
amplifiers as described above in relation to fluid viscosity dependent selector systems,
such as seen n Figure 12.
[0097] n another embodiment of a velocity or flow rate dependent autonomous
flow control system, a system utilizing a fluid ratio system, similar to that shown at ratio
control system 140 in Figure 5, is used. The ratio control system passageways 144 and
146 are modified, as necessary, to divide the fluid flow based on relative fluid flow rate
(rather than relative viscosity). A primary passageway 47 can be used if desired. The
ratio control system in this embodiment divides the flow into a ratio based on fluid
velocity. Where the velocity ratio is above a preselected amount (say, 1.0), the flow
control system is closed and resists flow. Where the velocity ratio is below the
predetermined amount, the system is open and fluid flow is relatively unimpeded. As the
velocity of fluid flow changes over time, the valve will open or close in response. A flow
ratio control passageway can be designed to provide a greater ra te of increase in
resistance to flow as a function of increased velocity above a target velocity in
comparison to the other passageway. Alternately, a passageway can be designed to
provide a lesser rate of increase in resistance to fluid flow as a function of fluid velocity
above a targeted velocity in comparison to the other passageway.
[0098] Another embodiment of a velocity based fluid valve is seen at Figures
17A-C, in which a fluid pathway dependent resistance system 950 is used to create a
bistable switch. The pathway dependent resistance system 950 preferably has only a
single inlet 954 and single outlet 958 in this embodiment, although other inlets and
outlets can be added to regulate flow, flow direction, eliminate eddies, etc. When the
fluid flows at below a preselected velocity or flow rate, the fluid tends to simply flow
through the vortex outlet 958 without substantial rotation about the vortex chamber 952
and without creating a significant pressure drop across the pathway dependent resistance
system 50 as seen in Figure 17A. As velocity or flow rate increases to above a
preselected velocity, as seen in Figure 17B, the fluid rotates about the vortex chamber
952 before exiting through outlet 958, thereby creating a greater pressure drop across the
system. The bistable vortex switch is then closed. As the velocity or flow rate decreases,
as represented in Figure C, the fluid continues to rotate about the vortex chamber 952
and continue to have a significant pressure drop. The pressure drop across the system
creates a corresponding back-pressure on the fluid upstream. When the velocity or flow
rate drops sufficiently, the fluid will return to the flow pattern seen in Figure 7A and the
switch will re-open. It is expected that a hysteresis effect will occur.
[0099] Such application of a bistable switch allows fluid control based on
changes in the fluid characteristic of velocity or flow rate. Such control is useful in
applications where it is desirable to maintain production or injection velocity or flow rate
at or below a given rate. Further application will be apparent to those skilled in the art.
(0100] The flow control systems as described herein may also utilize changes in
the density of the fluid over time to control fluid flow. The autonomous systems and
valves described herein rely upon changes in a characteristic of the fluid flow. As
described above, fluid viscosity and flow rate can be the fluid characteristic utilized to
control flow. In an example system designed to take advantage of changes in the fluid
characteristic of density, a flow control system as seen in Figure 3 provides a fluid ratio
system 40 which employs at least two passageways 44 and 46 wherein one passageway is
more density dependent than the other. Tha is, passageway 44 supplies a greater
resistance to flow for a fluid having a greater density whereas the other passageway 46 is
either substantially density independent or has an inverse flow relationship to density. In
such a way, as the fluid changes to a preselected density it is "selected" for production
and flows with relatively less resistance through the entire system 25 with less imparted
back-pressure; that is, the system or valve will be "open." Conversely, as the density
changes over time to an undesirable density, the flow ratio control system 40 will change
the output ratio and the system 25 will impart a relatively greater back-pressure; that is,
the valve is "closed."
[0101] Other flow control system arrangements can be utilized with a density
dependent embodiment as well. Such arrangements include the addition of amplifier
systems, pathway dependent resistance systems and the like as explained elsewhere
herein. Further, density dependent systems may utilize bistable switches and other fluidic
control devices herein.
[0102] In such a system, fluid is "selected" or the fluid selector valve is open
where the fluid density is above or below a preselected density. For example, a system
designed to select production of fluid when it is composed of a relatively greater
percentage of oil, is designed to select production of the fluid, or be open, when the fluid
is above a target density. Conversely, when the density of the fluid drops below the
target density, the system is designed to be closed. When the density dips below the
preselected density, the switch is "flipped" closed and fluid flow is resisted
[0103] The density dependent flow control system can utilize fluid amplifiers as
described above in relation to fluid viscosity dependent flow control systems, such as
seen in Figure 12. In one embodiment of a density dependent autonomous flow control
system, a system utilizing a fluid ratio system, similar to that shown at ra t io control
system 40 in Figure 5, is used. The ratio control system passageways 4 and 46 are
modified, as necessary, to divide the fluid flow based on relative fluid density (rather than
relative viscosity). A primary passageway 47 can be used if desired. The ratio control
system in this embodiment divides the flow into a ratio based on fluid density. Where the
density ratio is above (or below) a preselected ratio, the selector system is closed and
resists flow. As the density of fluid f ow changes over time, the valve will open or close
in response.
[0104] The velocity dependent systems described above can be utilized in the
steam injection method where there are multiple injection ports fed from the same steam
supply line. Often during steam injection, a "thief zone" is encountered which bleeds a
disproportionate amount of steam from the injection system. It is desirable to limit the
amouni of steam injected into the thief zone so that ail of the zones fed by a steam supply
receive appropriate amounts of steam.
[0105] Turning again to Figure 16, an injection well 200 with steam source
1201 and steam supply line(s) 1206 supplying steam to multiple injection port systems
1210 is utilized. The flow control systems 225 are velocity dependent systems, as
described above. The injection steam is supplied from the supply line 1206 to the ports
1210 and thence nto the formation 1204. The steam is injected through the velocity
dependent flow control system, such as a bistable switch 70, seen in Figure 5, at a
preselected "low" rate at which the switch does not exhibit bistability. The steam simply
flows into the outlets 184 and 186 in basically similar proportion. The outlets 184 and
6 are in fluid communication with the inlets 54 and 56 of the pathway dependent
resistance system. The pathway dependent resistance system 150 will thus not create a
significant back-pressure on the steam which will enter the formation with relatively
ease
(0106] If a thief zone is encountered, the steam flow rate through the flow
control system will increase above the preselected low injection rate to a relatively high
rate. The increased flow rate of the steam through the bistable switch will cause the
switch to become bistable. That is, the switch !70 will force a disproportionate amount
of the steam flow through the bistable switch outlet 84 and into the pathway dependent
resistance system 150 through the primarily tangentially-oriented inlet 54. Thus the
steam injection rate into the thief zone v/i be restricted by the autonomous fluid
selectors. (Alternately, the velocity dependent flow control systems can utilize the
pathway dependent resistance system shown at Figure 17 or other velocity dependent
systems described elsewhere to similar effect.)
[0107] t is expected that a hysteresis effect will occur. As the flow rate of the
steam increases and creates bistability in the switch 170, the flow rate through the flow
control system 25 will be restricted by the back-pressure created by the pathway
dependent resistance system 140 This, in turn, will reduce the flow rate to the
preselected low rate, at which time the bistable switch will cease to function, and steam
will again flow relatively evenly through the vortex inlets and into the formation without
restriction.
[0108] The hysteresis effect may result in "pulsing" during injection. Pulsing
during injection can lead to better penetration of pore space since the transient pulsing
will be pushing against the inertia of the surrounding fluid and the pathways into the
tighter pore space may become the path of least resistance. This is an added benefit to
the design where the pulsing is at the appropriate rate.
[0109] To "re-set" the system, or return to the initial flow partem, the operator
reduces or stops steam flow into the supply line. The steam supply is then re-established
and the bistable switches are back to their initial condition without bistability. The
process can be repeated as needed.
[0110] In some places, it is advantageous to have an autonomous flow control
system or valve that restricts production of injection fluid as it starts to break-through into
the production well, however, once the break-through has occurred across the entire well,
the autonomous fluid selector valve turns off. In other words, the autonomous fluid
selector valve restricts water production n the production well until the point is reached
where that restriction is hurting oil production from the formation. Once that point is
reached, the flow control system ceases restricting production into the production well.
[0111] In Figure 16, concentrating on the production well 1300, the production
tubing string 1308 has a plurality of production tubular sections 24, each with at least one
autonomous flow control system 25.
[0 2] In one embodiment, the autonomous flow control system functions as a
bistable switch, such as seen in Figure 7 at bistable switch 950. The bistable fluid
switch 950 creates a region where different pressure drops can be found for the same
flow rate. Figure 1 is a chart of pressure P versus flow rate Q illustrating the flow
through bistable switch, pathway dependent resistance system 950. At fluid flow rate
increases at region A, the pressure drop across the system gradually increases. When the
flow rate increases to a preselected rate, the pressure wi l jump, as seen at region B. As
the increased pressure leads to reduced flow rate, the pressure wil stay relatively high, as
seen at region C. If the flow rate drops enough, the pressure will drop significantly and
d e cycle can begin again. In practice the benefit of this hysteresis effect is that if the
operator knows what final position he wants the switch to be in, he can achieve it, by
either starting with a very s ow flow rate and gradually increasing it to the desired level,
or, starting with a very high flow rate and gradually decreasing it to the desired level.
[0113] Figure 19 is a schematic drawing showing a flow control system
according to one embodiment of the invention having a ratio control system, amplifier
system and pathway dependent resistance system, exemplary for use in inflow control
device replacement. Inflow Control Devices (ICD), such as commercially available from
Halliburton Energy Services, inc., under the trade name EquiFlow, for example. Influx
from the reservoir varies, sometimes rushing to an early breakthrough and other times
slowing to a delay. Either condition needs o be regulated so that valuable reserves can
be fully recovered. Some wells experience a "heel-toe" effect, permeability differences
and water challenges, especially in high viscosity oi reserves. An ICD attempts to
balance inflow or production across the completion string, improving productivity,
performance and efficiency, by achieving consistent flow along each production interval.
An CD typically moderates flow from high productivity zones and stimulates flow from
lower productivity zones. A typical ICD is installed and combined with a sand screen in
an unconsolidated reservoir. The reservoir fluid runs from the formation through the
sand screen and into the flow chamber, where it continues through one or more tubes.
Tube lengths and inner diameters are designed to induce the appropriate pressure drop to
move the flow through the pipe at a steady pace. The ICD equalizes the pressure drop,
yielding a more efficient completion and adding to the producing life as a result of
delayed water-gas coning. Production per unit length is also enhanced.
[01 14] The flow control system of Figure 19 is similar to that of Figures 5, 10
and 2 and so will not be discussed in detail. The flow control system shown in Figure
is velocity dependent or flow rate dependent. The ratio control system 040 has first
passageway 044 with first fluid flow restrictor 04 1 therein and a second inlet
passageways 1046 with a second flow restrictor 1043 therein. A primary passageway
1047 can be utilized as well and can also have a flow restriction 048. The restrictions in
t e passageways are designed to produce different pressure drops across the restrictions
as the fluid flow rate changes over ti e The flow restrictor in the primary passageway
can be selected to provide the same pressure drops over the same flow rates as the
restrictor n the first or second passageway.
[0 15] Figure 20 is a chart indicating the pressure, P, versus flow rate, Q, curves
for the first passageway 1044 (#1) and second passageway 1046 (#2), each with selected
restrictors. At a low driving pressure, line A, there will he more fluid flow in the first
passageway 1044 and proportionately less fluid flow in the second passageway 1046.
Consequently, the fluid flow leaving the amplifier system will be biased toward outlet
1086 and into the vortex chamber 052 through radial inlet 1056 The fluid will not
rotate substantially in the vortex chamber and the valve will be open, allowing flow
without imparting substantial back-pressure. At a high driving pressure, such as at ine
B, the proportionate fluid flow through the first and second passageways will reverse and
fluid will be directed into the vortex chamber primarily tangentially creating a relatively
large pressure drop, imparting back-pressure to the fluid and closing the valve.
[01 6 ] In a preferred embodiment where production is sought to be limited at
higher driving pressures, the primary passageway restrictor is preferably selected to
mimic the behavior of the restrictor in the first passageway 1044. Where the restriction
1048 behaves in a manner similar to restrictor 1041 , the restriction 1048 allows less fluid
flow at the high pressure drops, thereby restricting fluid flow through the system.
[0 7] The flow restrictors can be orifices, viscous tubes, vortex diodes, etc.
Alternately, the restrictions can be provided by spring biased members or pressuresensitive
components as known in the art. I the preferred embodiment, restriction 104
in the first passageway 1044 has flexible "whiskers" which block flow at a low driving
pressure but bend out of the way at a high pressure drop and allow flow.
[0118] This design for use as an CD provides greater resistance to flow once a
specified flow rate is reached, essentially allowing the designer to pick the top rate
through the tubing string section.
[0119] Figure 2 1 shows an embodiment of a flow control system according to
the invention having multiple valves in series, with an auxiliary flow passageway and
secondary pathway dependent resistance system.
[0120] A first fluid selector valve system 00 is arranged in series with a
second fluidic valve system 1102. The first flow control system 1100 is similar to those
described herein and will not be described in detail The first fluid selector valve
includes a flow ratio control system 1140 with first, second and primary passageways
144, 146 and 47, a fluid amplifier system 1170, and a pathway dependent resistance
system 11 0, namely, a pathway dependent resistance system with vortex chamber 1152
and outlet 1 58. The second fluidic valve system 102 in the preferred embodiment
shown has a selective pathway dependent resistance system 1 10, in this case a pathway
dependent resistance system. The pathway dependent resistance system 1110 has a radial
inlet 104 and tangential inlet 1106 and outlet 1108.
[0121] When a fluid having preferred viscosity (or flow rate) characteristics, to
be selected, is flowing through the system, then the first flow control system will behave
in an open manner, allowing fluid flow without substantial back-pressure being created,
with fluid flowing through the pathway dependent resistance system 150 of the first
valve system primarily radially. Thus, minimal pressure drop will occur across the first
valve system. Further, the fluid leaving the first valve system and entering the second
valve system through radial inlet 04 will create a substantially radial flow partem in the
vortex chamber 1 2 of the second valve system. A minimal pressure drop will occur
across the second valve system as well. This two-step series of autonomous fluid selector
valve systems allows for looser tolerance and a wider outlet opening in the pathway
dependent resistance system 1150 of the first valve system 00.
[0122] The inlet 1 04 receives fluid from auxiliary passageway 1197 which is
shown fiuidiy connected to the same fluid source 142 as the first autonomous valve
system 1100. Alternately, the auxiliary passageway 97 can be in fluid communication
with a different fluid source, such as fluid from a separate production zone along a
production tubular. Such an arrangement would allow the fluid flow rate at one zone to
control fluid flow in a separate zone. Alternatively, the auxiliary passageway can be fluid
flowing from a lateral borehole while the fluid source for the first valv system 1100 is
received from a flow line to the surface. Other arrangements will be apparent. It should
be obvious that the auxihary passageway can be used as the control input and the
tangential and radial vortex inlets can be reversed. Other alternatives can be employed as
described elsewhere herein, such as addition or subtraction of amplifier systems, flow
ratio control modifications, vortex modifications and substitutes, etc.
[0123] Figure 22 is a schematic of a reverse cementing system 1200. The
wellbore 202 extends into a subterranean formation 204. A cementing string 1206
extends into the wellbore 02 typically inside a casing. The cementing string 1206 can
be of any kind known in the art or discovered later capable of supplying cement into the
wellbore in a reverse cementing procedure. During reverse cementing, the cement 1208
is pumped into the annulus 1210 formed between the wall of the wellbore 1202 and the
cementing string 1206. The cement, flow of which is indicated by arrows 1208, is
pumped into the annulus 1 10 at an uphole location and downward through the annulus
toward the bottom of the wellbore. The annulus thus fills from the top downward
During the procedure, the flow of cement and pumping fluid 1208, typically water or
brine, is circulated down the annulus to the bottom of the cementing string, and then back
upward through the interior passageway 12 18 of the string.
[0 4] Figure 22 shows a flow control system 25 mounted at or near the bottom
of the cement string 1206 and selectively allowing fluid flow from outside the cementing
string into the interior passageway 2 18 of the cement string. The flow control system 25
is of a design similar to that explained herein in relation to Figure 3, Figure 5, Figure
or Figure 12. The flow control system 25 includes a ratio control system 40 and a
pathway dependent resistance system 50. Preferably the system 25 includes at least one
fluid amplifier system 70. The plug 1222 seals flow except for through the autonomous
fluid selector valve.
[0125] The flow control system 25 is designed to be open, with the fluid directed
primarily through the radial inlet of the pathway dependent resistance system 50, when a
lower viscosity fluid, such as pumping fluid, such as brine, is flowing through the system
25. As the viscosity of the fluid changes as cement makes its way down to the bottom of
the vvellbore and cement begins to flow tiirough the flow control system 25, the selector
system closes, directing the now higher viscosity fluid (cement) through the tangential
inlet of the pathway dependent resistance system 50. Brine and water flows easily
through the selector system since the valve is open when such fluids are flowing through
the system. The higher viscosity cement (or other non-selected fluid) will cause the valve
to close and measurably increase the pressure read at the surface.
[0126] n an alternate embodiment, multiple flow control systems in parallel are
employed. Further, although the preferred embodiment has all fluid directed tiirough a
single flow control system, a partial flow from the exterior of the cement string could be
directed through the fluid selector.
[0127] For added pressure increase, the plug 1222 can be mounted on a sealing
or closing mechanism that seals the end of the cement string when cement flow increases
the pressure drop across the plug. For example, the flow control system or systems can
be mounted on a closing or sealing mechanism, such as a piston-cylinder system, flapper
valve, ball valve or the like in which increased pressure closes the mechanism
components. As above, the selector valve is open where the fluid is of a selected
viscosity, such as brine, and little pressure drop occurs across tire plug. When the closing
mechanism s initially in an open position, the fluid flows through and past the closing
mechanism and upwards through the interior passageway of the string. When the closing
mechanism is moved to a closed position, fluid is prevented from flowing into the interior
passageway from outside the string. When the mechanism is in the closed position, all of
the pumping fluid or cement is directed through the flow control system 25.
[0128] When the fluid changes to a higher viscosity, a greater back-pressure is
created on the fluid below the selector system 25. This pressure is then transferred to the
closing mechanism. This increased pressure moves the closing mechanism to the closed
position. Cement is thus prevented from flowing into the interior passageway of the
cement string.
[0129] In another alternative, a pressure sensor system can be employed. When
the fluid moving through the fluid amplifier system changes to a higher viscosity, due to
the presence of cement in the fluid, the flow control system creates a greater back¬
pressure on the fluid as described above. This pressure increase is measured by the
pressure sensor system and read at the surface. The operator then stops pumping cement
knowing that the cement has fiiied the annulus and reached the bottom of the cement
string.
[0130] Figure 23 shows a schematic view of a preferred embodiment of the
invention. Note that the two inlets 54 and 56 to the vortex chamber 52 are not perfectly
aligned to direct fluid flow perfectly tangentially (i.e., exactly 90 degrees to a radial line
from the vortex center) nor perfectly radially (i.e., directly towards the center of the
vortex), respectively. Instead, the two inlets 54 and 56 are directed in a rotation
maximizing pathway and a rotation minimizing pathway, respectively. In many respects,
Figure 23 is similar to Figure 12 and so wi l not be described at length here. Like
numbers are used to Figure 2 . Optimizing the arrangements of the vortex inlets is a step
that can be carried out using, for example, Computational Flow Dynamics models.
[0131] Figures 24A-D shows other embodiments of the inventi ve pathway
dependent resistance system. Figure 24A shows a pathway dependent resistance system
with only one passageway 1354 entering the vortex chamber. The flow control system
340 changes the entrance angle of the fluid as it enters the chamber 352 rom this
single passageway. Fluid flow F through the fluid ratio controller passageways 1344 and
46 will cause a different direction of the fluid jet at the outlet 1380 of the fluid ratio
controller 340. The angle of the jet will either cause rotation or will minimize rotation
in the vortex chamber 1350 by the fluid before it exits the chamber at outlet 1358.
[0132] Figure 24B-C is another embodiment of the pathway dependent
resistance system 1450, in which the two inlet passageways both enter the vortex
chamber primarily tangentially. When the flow is balanced between the passages 1454
and 1456, as shown in Figure 24 the resulting flow in the vortex chamber 1452 has
minimal rotation before exiting outlet 1458. When the flow down one of the
passageways is greater than the flow down the other passage way, as shown in Figure
24C, the resulting flow in the vortex chamber 1452 wil l have substantial rotation prior to
flowing through outlet 1458. The rotation in the flow creates back pressure on the fluid
upstream n the system. Surface features, exit path orientation, and other fluid path
features can be used to cause more flow resistance to one direction of rotation (such as
counter-clockwise rotation) than to another direction of rotation (such as clockwise
rotation).
[0133] n Figure 24D, multiple inlet tangential paths i 554 and multiple inlet
radial paths 1556 are used to minimize the flow jet interference to the inlet of the vortex
chamber 1552 in pathway dependent resistance system 550. Thus, the radial path can be
split into multiple radial inlet paths directed into the vortex chamber 552. Similarly, the
tangential path can be divided into multiple tangential inlet paths. The resultant fluid
flow in the vortex chamber 552 is determined at least in part by the entry angles of the
multiple inlets. The system can be selectively designed to create more or less rotation of
the fluid about the chamber 1552 prior to exiting through outlet 1558.
[0134] Note that in the fluid flow control systems described herein, the fluid
flow in the systems is divided and merged into various streams of flow, but that the fluid
is not separated into its constituent components; that is, the flow control systems are not
fluid separators.
[0135] For example, where the fluid is primarily natural gas, the flow ratio
between the first and second passageways may reach 2 1 since the First passageway
provides relatively little resistance to the flow of natural gas. The flow ratio will lower, or
even reverse, as the proportional amounts of the fluid components change. The same
passageways may result in a :1 or even a 1:2 flow ratio where the fluid is primarily oil.
Where the fluid has both oil and natural gas components the ratio will fall somewhere in
between. As the proportion of the components of the fluid change over the life of the
well the flow ratio through the ratio control system will change. Similarly, the ratio will
change if the fluid has both water and oil components based on the relative characteristic
of the water and o l components. Consequently, the fluid ratio control system can be
designed to result i the desired fluid flow ratio.
[0136] The flow control system is arranged to direct flow of fluid having a larger
proportion of undesired component, such as natural gas or water, into the vortex chamber
primarily tangentially, thereby creating a greater back-pressure on the fluid than if it was
allowed to flow upstream without passing through the vortex chamber. This back¬
pressure will result in a lower production rate of the fluid from the formation along the
production interval than would occur otherwise.
[0137] For example, in an oil well, natural gas production is undesired. As the
proportion of natural gas in the fluid increases, thereby reducing the viscosity of the fluid,
a greater proportion of fluid is directed into the vortex chamber through the tangential
inlet. The vortex chamber imparts a back-pressure on the fluid thereby restricting flow of
the fluid. As the proportion of fluid components being produced changes to a higher
proportion of oil (for example, as a result of oil in the formation reversing a gas draw¬
down), the viscosity of the fluid wi increase. The fluid ratio system will, in response to
the characteristic change, lower or reverse the ratio of fluid flow through its first and
second passageways. As a result, a greater proportion of the fluid will be directed
primarily radially into the vortex chamber. The vortex chamber offers less resistance and
creates less back-pressure on fluid entering the chamber primarily radially.
[0138] The above example refers to restricting natural gas production where oil
production is desired. The invention can also be applied to restrict water production
where oil production is desired, or to restrict water production when gas production is
desired.
[0139] The flow control system offers the advantage of operating autonomously
in the well. Further, the system has no moving parts and is therefore not susceptible to
being "stuck" as fluid control systems with mechanical valves and the like. Further, the
flow control system will operate regardless of the orientation of the system in the
wellbore, so the tubular containing the system need not be onented in the wellbore. The
system wi l operate in a vertical or deviated wellbore.
[0140] While the preferred flow control system is completely autonomous,
neither the inventive flow direction control system nor the inventive pathway dependent
resistance system necessarily have to be combined with the preferred embodiment of the
other. So one system or the other could have moving parts, or electronic controls, etc.
[0141] For example, while the pathway dependent resistance system is
preferably based on a vortex chamber, it could be designed and built to have moving
portions, to work with the ratio control system. To wit, two outputs from the ratio control
system could connect to either side of a pressure balanced piston, thereby causing the
piston to be able to shift from one position to another. One position would, for instance,
cover an exit port, and one position would open it. Hence the ratio control system does
not have to have a vortex-based system to allow one to enjoy the benefit of the inventive
ratio control system. Similarly, the inventive pathway dependent resistance system could
be utilized with a more traditional actuation system, including sensors and valves. The
inventive systems could also include data output subsystems, to send data to the surface,
to allow operators to see the status of the system.
[0142] The invention can also be used with other flow control systems, such as
inflow control devices, s ding sleeves, and other flow control devices that are already
well known in the industry. The inventive system can be either parallel with or in series
with these other flow control systems.
[0143] While this invention has been described with reference to illustrative
embodiments, this description is not intended to be construed in a limiting sense. Various
modifications and combinations of the illustrative embodiments as well as other
embodiments of the invention, will be apparent to persons skilled in the art upon
reference to the description. It is, therefore, intended that d e appended claims encompass
any such modifications or embodiments.

It is claimed:
1. An apparatus for controlling flow of fluid comprising;
a flow ratio control system having at least a first passageway and a second passageway, wherein the ratio of fluid flow through the first passageway and second passageway is related to the characteristic of the fluid flow and wherein the ratio of flow between the two passageways will alter with changes in the characteristic of the fluid flow, and wherein the output of the flow ratio control system is utilized to control a pathway dependent resistance system.
2. An apparatus as in claim 1, wherein the characteristic is viscosity.
3. An apparatus as in claim 1, wherein the characteristic is fluid flow rate.
4. An apparatus as in claim 1, wherein the characteristic is density.
5. An apparatus as in claim 2, wherein the first passageway of the fluid ratio control system is more viscosity-dependent than the second passageway.
6. An apparatus as in claim 5 wherein the first passageway of the fluid ratio control system has a consistent diameter along its length.
7. An apparatus as in claim 6 wherein the first passageway of the flow ratio control system will provide more resistance to fluid flow as the fluid viscosity increases.
8. An apparatus as in claim 6 wherein the first passageway of the fluid ratio control system is longer than the second passageway of the fluid ratio control system.
9. An apparatus as in claim 5 wherein the first passageway provides a tortuous flow path.
10. An apparatus as in claim 5 wherein the first passageway has a textured interior surface.
11. An apparatus as in claim 5 wherein the first passageway is made of a swellable material, the passageway constricting when the materia! swells.
12. An apparatus as in claim 5 wherein the swellable material swells when contacted by the fluid when an undesired component is present in the fluid.
13. An apparatus as in claim 5 wherein the second passageway of the fluid ratio system will provide less resistance to fluid flow than the first passageway when the fluid viscosity is higher than a target viscosity.
14. An apparatus as in claim 5 wherein the increase in resistance to fluid flow in the second passageway in response to an increase in viscosity of the fluid is less than the increase in resistance to fluid flow in the first passageway.
15. An apparatus as in claim 5 wherein the second passageway of the fluid ratio system provides substantially constant resistance to fluid flow regardless of changes in fluid viscosity.
16. An apparatus as in claim 15 wherein the second passageway has a plurality of flow restrictors therein.
17. An apparatus as in claim 16 wherein the flow restrictors are orifice plates.
18. An apparatus as in claim 14 wherein the second passageway further comprises a vortex diode.
19. An apparatus as in claim 1, wherein the pathway dependent resistance system will impart a back-pressure on fluid flowing through the apparatus.
20. An apparatus as in claim 1 wherein the pathway dependent resistance system further comprises a vortex assembly.
21. An apparatus as in claim 20 wherein the vortex assembly comprises a first and second inlet, a vortex chamber and an outlet.
22. An apparatus as in claim 21 wherein the first inlet of the vortex assembly is in fluid communication with the first passageway of the flow ratio control system and wherein the second inlet of the vortex assembly is in fluid communication with the second passageway of the flow ratio control system.
23. An apparatus as in claim 21 wherein the vortex assembly further comprises at least a second outlet.
24. An apparatus as in claim 22 wherein the first inlet of the vortex assembly will direct fluid into the vortex chamber primarily tangentially.
25. An apparatus as in claim 22 wherein the second inlet of the vortex assembly will direct fluid into the vortex chamber primarily radially.
26. An apparatus as in claim 24 wherein the first inlet directs fluid into the vortex chamber at an angle substantially normal to a radial line extending from the vortex outlet.
27. An apparatus as in claim 25 wherein the second inlet directs fluid into the vortex chamber substantially in line with the vortex outlet.
28. An apparatus as in claim 20 wherein the vortex assembly comprises a vortex chamber, at least one outlet, and multiple inlets which direct fluid into the vortex chamber primarily tangentially.
29. An apparatus as in claim 28 wherein the vortex assembly further comprises multiple inlets which direct fluid into the vortex chamber primarily radially.
30. An apparatus as in claim 20 wherein the pathway dependent resistance system comprises at least two vortex assemblies connected in parallel.
31. An apparatus as in claim 30 wherein the pathway dependent resistance system comprises at least two vortex assemblies connected in series.
32. An apparatus as in claim 31 wherein the pathway dependent resistance system comprises a first and second vortex assemblies, each vortex assembly having a vortex chamber, a first and second inlets and an outlet, the first inlet of the second vortex assembly in fluid communication with the outlet of the first vortex assembly.
33. An apparatus as in claim 32 wherein the first inlet of the second vortex assembly directs fluid into the vortex chamber of the second vortex assembly primarily radially.
34. An apparatus as in claim 20 wherein the vortex assembly comprises a cylindrical vortex assembly.
35. An apparatus as in claim 1 further comprising a fluid amplifier system interposed between the fluid ratio system and the pathway dependent resistance system and in fluid communication with both.
36. An apparatus as in claim 35 wherein the fluid amplifier system comprises a proportional amplifier.
37. An apparatus as in claim 35 wherein the fluid amplifier system comprises a pressure-type amplifier.
38. An apparatus as in claim 35 wherein the fluid amplifier system comprises a jet-type amplifier.
39. An apparatus as in claim 35 wherein the fluid amplifier system comprises a bistable amplifier.
40. An apparatus as in claim 35 wherein the fluid ratio system further comprises a primary flow passageway, the primary flow passageway in fluid communication with the fluid amplifier system.
41. An apparatus as in claim 40 wherein the primary passageway further comprises a vortex diode.
42. An apparatus as in claim 40 wherein the primary passageway will accommodate more fluid flow than either the first or second passageways.
43. An apparatus as in claim 40 wherein the primary passageway will accommodate more flow than the first and second passageways combined.
44. An apparatus as in claim 40 wherein the first and second passageways of the flow ratio control system will direct flow from the primary passageway.
45. An apparatus as in claim 1 further comprising multiple fluid amplifier systems interposed between the fluid ratio system and the pathway dependent resistance system, the fluid amplifier systems arranged in series.
46. An apparatus as in claim 45 wherein the multiple fluid amplifier systems comprise at least one proportional amplifier and at least one bistable amplifier.
47. An apparatus as in claim 45 wherein the multiple fluid amplifier systems comprise at least one pressure-type amplifier and at least one bistable amplifier.
48. An apparatus as in claim 3, wherein the first passageway of die fluid ratio control system will provide less resistance than the second passageway to fluid flow as the flow rate increases.
49. An apparatus as in claim 3, wherein the second passageway of the fluid ratio control system will provide more resistance than the first passageway to fluid flow as the flow rate increases.
50. An apparatus as in claim 3, wherein the flow ratio control system comprises a bistable switch.
51. An apparatus as in claim 3, wherein the second passageway of the fluid ratio system will provide less resistance to fluid flow than the first passageway when the fluid flow rate is lower than a target flow rate.
52. An apparatus as in claim 3, wherein the second passageway of the fluid ratio system provides substantially constant resistance to fluid flow regardless of changes in fluid flow rate.
53. An apparatus as in claim 3, wherein the pathway dependent resistance system further comprises a vortex assembly having a first and second inlet, a vortex chamber and an outlet.
54. An apparatus as in claim 53, wherein the first inlet of the vortex assembly is in fluid communication with the first passageway of the flow ratio control system and wherein the second inlet of the vortex assembly is in fluid communication with the second passageway of the flow ratio control system.
55. An apparatus as in claim 54, wherein the first inlet of the vortex assembly will direct fluid into the vortex chamber primarily tangentially, and wherein the second inlet of the vortex assembly will direct fluid into the vortex chamber primarily radially.
56. An apparatus as in claim 3, further comprising a fluid amplifier system interposed between the fluid ratio system and the pathway dependent resistance system and in fluid communication with both.
57. An apparatus as in claim 56 wherein the fluid ratio system further comprises a primary flow passageway, the primary flow passageway in fluid communication with the fluid amplifier system.
58. AJI apparatus as in claim 4, wherein the first passageway of the fluid ratio control is more density dependent than the second passageway.
59. An apparatus as in claim 58, wherein the second passageway will provide substantially constant resistance to fluid flow as the density changes.
60. An apparatus as in claim 58, wherein the second passageway will provide less resistance to fluid flow as the flow rate increases.
61. An apparatus as in claim 4, wherein the second passageway of the fluid ratio system will provide less resistance to fluid flow than the first passageway when the fluid density is higher than a target density.
62. An apparatus as in claim 68, wherein the pathway dependent resistance system further comprises a vortex assembly having a first and second inlet, a vortex chamber and an outlet.
63. An apparatus as in claim 62, wherein the first inlet of the vortex assembly is in fluid communication with the first passageway of the flow ratio control system and wherein the second inlet of the vortex assembly is in fluid communication with the second passageway of the flow ratio control system.
64. An apparatus as in claim 63, wherein the first inlet of the vortex assembly will direct fluid into the vortex chamber primarily tangentially, and wherein the second inlet of the vortex assembly will direct fluid into the vortex chamber primarily radially.
65. An apparatus as in claim 58, further comprising a fluid amplifier system interposed between the fluid ratio system and the pathway dependent resistance system and in fluid communication with both.
66. An apparatus as in claim 65 wherein the fluid ratio system further comprises a primary flow passageway, the primary flow passageway in fluid communication with the fluid amplifier system.
67. An apparatus as in claim 1 wherein the apparatus is an oilfield tubular for positioning downhole in a wellbore extending through a subterranean formation.
68. An apparatus as in claim 67, wherein the flow control system is positioned in the wall of the oilfield tubular.
69. An apparatus as in claim 68, wherein the oilfield tubular has an interior passageway in fluid communication with the flow ratio control system.
70. An apparatus as in claim 69, wherein formation fluid will flow from the formation into the tubular interior passageway.
71. An apparatus as in claim 69, wherein the apparatus is for controlling production fluid flow and wherein the apparatus selects oil production over natural gas production.
72. An apparatus as in claim 69, wherein the apparatus is for controlling production fluid flow and wherein the apparatus selects natural gas production over water production.
73. An apparatus as in claim 69, wherein the apparatus is for controlling production fluid flow and wherein the apparatus selects oil production over water production.
74. An apparatus as in claim 71, wherein the apparatus will provide higher resistance to flow as the composition of the formation fluid changes to a higher percentage of natural gas.
75. An apparatus as in claim 5, wherein the flow control system is positioned in an oilfield tubular, and wherein the apparatus is for controlling production fluid flow, and
wherein the apparatus will increase resistance to fluid flow when the formation fluid reaches a target percentage composition of natural gas.
76. An apparatus as in claim 48, wherein the flow control system is positioned in an oilfield tubular, and wherein the apparatus is for controlling production fluid flow, and wherein the apparatus selects oil production over natural gas production.
77. An apparatus as in claim 58, wherein the flow control system is positioned in an oilfield tubular, and wherein the apparatus is for controlling production fluid flow, and wherein the apparatus selects oil production over natural gas production.
78. An apparatus as in claim 68, further comprising a plurality of flow ratio control systems and pathway dependent resistance systems.
79. An apparatus as in claim 48, wherein the flow control system is positioned in an oilfield tubular, and wherein the apparatus is for controlling production fluid flow, and wherein the apparatus will provide increased resistance to flow when flow rate is above a target flow rate.
80. An apparatus as in claim 67, the apparatus for injecting injection fluid from the oilfield tubular into the formation.
81. An apparatus as in claim 80, wherein the apparatus is for controlling injection of the injection fluid into the formation.
82. An apparatus as in claim 81, wherein the injection fluid is steam.
83. An apparatus as in claim 81, wherein the injection fluid is carbon dioxide.
84. An apparatus as in claim 82, wherein the apparatus selects injection of steam over injection of water.
85. An apparatus as in claim 84, wherein the apparatus will provide lower resistance to flow as the composition of the injection fluid changes to a higher percentage of steam.
86. An apparatus as in claim 5, wherein the apparatus is an oilfield tubular for positioning downhole in a wellbore extending through a subterranean formation, and
wherein the apparatus is for controlling injection fluid flow, and wherein the apparatus will decrease resistance to injection fluid flow when the injection fluid reaches a target percentage composition of steam.
87. An apparatus as in claim 48, wherein the apparatus is an oilfield tubular for positioning downhole in a wellbore extending through a subterranean formation, and wherein the apparatus is for controlling injection fluid flow, and wherein the apparatus will decrease resistance to injection fluid flow when the injection fluid falls below a target flow rate.
88. An apparatus as in claim 58, wherein the apparatus is an oilfield tubular for positioning downhole in a wellbore extending through a subterranean formation, and wherein the apparatus is for controlling injection fluid flow, and wherein the apparatus will decrease resistance to injection fluid flow when the density of the injection fluid falls below a target density.
89. An apparatus as in claim 67, wherein the apparatus is for controlling flow of cementing fluid from the exterior of the oilfield tubular to the interior of the oilfield tubular during reverse cementing.
90. An apparatus as in claim 89, wherein the apparatus will provide higher resistance to flow of cementing fluid as the composition of the cementing fluid changes to a higher viscosity.
91. An apparatus as in claim 89, wherein the apparatus will provide higher resistance to flow of cementing fluid as the composition of the cementing fluid changes to a higher density.
92. An apparatus as in claim 89, wherein the apparatus will provide higher resistance to flow of cementing fluid as the composition of the cementing fluid changes to a higher flow rate.
93. An apparatus as in claim 89, further comprising a movable plug mounted in an interior passageway of the oilfield tubular and operable to restrict fluid flow into the interior passageway.
94. An apparatus as in claim 97, wherein the flow ratio control system and pathway dependent resistance system are positioned within the movable plug.
95. An apparatus as in claim 71, further comprising a screen assembly for sand control.
96. An apparatus as in claim 71, further comprising an inflow control device in fluid communication with the flow ratio control system.
97. An apparatus as in claim. 71, further comprising a plurality of apparatus spaced along the wellbore.
98. An apparatus as in claim 97, wherein the plurality of apparatus are positioned in a production string, the production string for extending through the wellbore along a production zone of the formation.
99. An apparatus as in claim 3, wherein the first passageway will provide a greater rate of increase in resistance in response to increased flow rate than the second passageway.
100. An apparatus as in claim 3, wherein the second passageway will provide a lesser rate of increase in resistance in response to increased flow rate than the first passageway.
101. A pathway dependent resistance system, comprising:
a vortex chamber;
at least a first inlet; and
an outlet, the first inlet of the pathway dependent resistance system in fluid communication with a flow direction control system, the flow from the flow direction control system affecting direction flow takes into the pathway dependent resistance system.
102. An apparatus as in claim 101, wherein the direction fluid flow takes into the pathway dependent resistance system is dependent on fluid viscosity.
103. An apparatus as in claim 101, wherein the direction fluid flow takes into the pathway dependent resistance system is dependent on fluid flow rate.
104. An apparatus as in claim 101, wherein the direction fluid flow takes into the pathway dependent resistance system is dependent on fluid density.
105. An apparatus as in claim 102, wherein the pathway dependent resistance system comprises a first and second inlet.
106. An apparatus as in claim 101 wherein the vortex assembly further comprises at least a second outlet.
107. An apparatus as in claim 105 wherein the first inlet of the vortex assembly will direct fluid into the vortex chamber primarily tangentially.
108. An apparatus as in claim 105 wherein the second inlet of the vortex assembly will direct fluid into the vortex chamber primarily radially.
109. An apparatus as in claim 101 wherein the at least one inlet comprises multiple inlets which direct fluid into the vortex chamber primarily tangentially.
110. An apparatus as in claim 101 wherein the at least one inlet comprises multiple inlets which direct fluid into the vortex chamber primarily radially.
111. An apparatus as in claim 101 wherein the at least one inlet comprises at least one inlet for directing fluid into the vortex chamber primarily radially and at least one inlet for directing fluid into the vortex chamber primarily tangentially.
112. An apparatus as in claim 101, further comprising a second vortex chamber, second vortex chamber outlet, and second vortex chamber inlet, the second vortex chamber inlet in fluid communication with the pathway dependent resistance system outlet.
113. An apparatus as in claim 112 wherein the inlet of the second vortex assembly directs fluid into the vortex chamber of the second vortex assembly primarily radially.
114. An apparatus as in claim 112, further comprising a second inlet to the second vortex chamber.
115. An apparatus as in claim 101 wherein the vortex chamber comprises a cylindrical vortex chamber.
116. An apparatus as in claim 101, wherein the flow direction control system comprises multiple passageways.
117. An apparatus as in claim 116, wherein the multiple passageways are in fluid communication with the pathway dependent resistance system inlet.
118. An apparatus as in claim 101, wherein the flow direction control system comprises a flow ratio control system having at least a first and second passageway.
119. An apparatus as in claim 118, wherein the first passageway of the fluid ratio control system is more viscosity-dependent than the second passageway.
120. An apparatus as in claim 119 wherein the first passageway of the flow ratio control system will provide a greater increase in resistance to fluid flow than the second passageway as the fluid viscosity increases.
121. An apparatus as in claim 119 wherein the second passageway of the fluid ratio system will provide less resistance to fluid flow than the first passageway when the fluid viscosity is higher than a target viscosity.
122. An apparatus as in claim 119 wherein the second passageway of the fluid ratio system provides substantially constant resistance to fluid flow regardtess of changes in fluid viscosity.
123. An apparatus as in claim 119 wherein the second passageway further comprises a vortex diode.
124. An apparatus as in claim 101, wherein the pathway dependent resistance system will impart a back-pressure on fluid flowing through the apparatus.
125. An apparatus as in claim 118, wherein the first passageway of the flow ratio control system is in fluid communication with the first inlet of the pathway dependent resistance system.
126. An apparatus as in claim 125, wherein the second passageway of the flow ratio control system is in fluid communication with a second inlet of the pathway dependent resistance system.
127. An apparatus as in claim 125, wherein the first and second passageways of the flow ratio control system are both in fluid communication with the first inlet of the pathway dependent resistance system.
128. An apparatus as in claim 103, wherein the fluid will flow into the vortex chamber primarily radially when the fluid flow rate is below a target rate.
129. An apparatus as in claim 128, wherein the fluid will flow into the vortex chamber primarily tangentially when the fluid flow rate is above a target rate.
130. An apparatus as in claim 129, wherein the fluid will continue to flow into the vortex chamber primarily tangentially when the fluid flow rate increases above a target rate and then decreases below the target rate.
131. An apparatus as in claim 103, wherein the flow direction control system comprises a flow ratio system having at least a first and second passageway.
132. An apparatus as in claim 131, wherein the flow ratio system comprises a bistable switch.
133. An apparatus as in claim 131, wherein the second passageway of the fluid ratio system will provide less resistance to fluid flow than the first passageway when the fluid flow rate is lower than a target flow rate.
134. An apparatus as in claim 131, wherein the second passageway of the fluid ratio system provides substantially constant resistance to fluid flow regardless of changes in fluid flow rate.
135. An apparatus as in claim 131, wherein the first inlet of the pathway dependent resistance system is in fluid communication with the first passageway of the flow ratio control system.
136. An apparatus as in claim 135, wherein the pathway dependent resistance system has a second inlet and the second inlet is in fluid communication with the second passageway of the flow ratio control system.
137. An apparatus as in claim 131, further comprising a fluid amplifier system interposed between the fluid ratio system and the pathway dependent resistance system and in fluid communication with both.
138. An apparatus as in claim 137, wherein the fluid ratio system further comprises a primary flow passageway, the primary flow passageway in fluid communication with the fluid amplifier system.
139. An apparatus as in claim 104, wherein the fluid will flow into the vortex chamber primarily radially when the fluid density is above a target rate.
140. An apparatus as in claim 139, wherein the fluid will flow into the vortex chamber primarily tangentially when the fluid density is below a target rate.
141. An apparatus as in claim 104, wherein the flow direction control system comprises a flow ratio system having at least a first and second passageway.
142. An apparatus as in claim 141, wherein the first passageway of the fluid ratio control is more density dependent than the second passageway.
143. An apparatus as in claim 141, wherein the second passageway of the fluid ratio system will provide less of an increase in resistance to fluid flow than the first passageway when the fluid density increases.
144. An apparatus as in claim 101, wherein the pathway dependent resistance system is positioned in an oilfield tubular for positioning downhole in a wellbore extending through a subterranean formation.
145. An apparatus as in claim 144, wherein the pathway dependent resistance system is for controlling production fluid flow and wherein the apparatus selects natural gas production over water production.
146. An apparatus as in claim 144, wherein the pathway dependent resistance system is for controlling production fluid flow and wherein the apparatus selects oil production over water production.
147. An apparatus as in claim 144, wherein the pathway dependent resistance system is for controlling production fluid flow and wherein the apparatus selects oil production over natural gas production.
148. An apparatus as in claim 144, wherein the pathway dependent resistance system is for controlling the injection of injection fluid into the formation.
149. An apparatus as in claim 148, wherein the injection fluid is steam.
150. An apparatus as in claim 149, wherein the pathway dependent resistance system selects injection of steam over injection of water.
151. An apparatus as in claim 150, wherein the pathway dependent resistance system will provide lower resistance to flow as the composition of the injection fluid changes to a higher percentage of steam.
152. A flow control system, comprising:
a flow ratio control system having at least a first passageway and a second passageway, wherein the ratio of fluid flow through the first passageway and second passageway is related to the characteristic of the fluid flow; and
a pathway dependent resistance system having a vortex chamber with at least a first inlet and an outlet, the first inlet of the pathway dependent resistance system in fluid communication with either the first or second passageway or both of the fluid ratio control system, variations in the ratio of flow coming from the first and second passageway affecting the relative resistance of the total fluid moving through the pathway dependent resistance system.
153. An apparatus as in claim 152, wherein the characteristic is viscosity.
154. An apparatus as in claim 152, wherein the characteristic is fluid flow rate.
155. An apparatus as in claim 152, wherein the characteristic is density.
156. An apparatus as in claim. 153, wherein the first passageway of the fluid ratio control system is more viscosity-dependent than the second passageway.
157. An apparatus as in claim 156 wherein the first passageway of the fluid ratio control system has a consistent diameter along its length.
158. An apparatus as in claim 156 wherein the first passageway of the flow ratio control system will provide a greater increase in resistance to fluid flow than the second passageway as the fluid viscosity increases.
159. An apparatus as in claim 153 wherein the second passageway of the fluid ratio system will provide less resistance to fluid flow than the first passageway when the fluid viscosity is higher than a target viscosity.
160. An apparatus as in claim 156 wherein the second passageway of the fluid ratio system provides substantially constant resistance to fluid flow regardless of changes in fluid viscosity.
161. An apparatus as in claim 156 wherein the second passageway further comprises a vortex diode.
162. An apparatus as in claim 152, wherein the pathway dependent resistance system will impart a back-pressure on fluid flowing through the apparatus.
163. An apparatus as in claim 152 wherein the first inlet of the vortex assembly is in fluid communication with the first passageway of the flow ratio control system and wherein the second inlet of the vortex assembly is in fluid communication with the second passageway of the flow ratio control system.
164, An apparatus as in claim 152 wherein the vortex assembly further comprises at
least a second outlet.
165. An apparatus as in claim 152 wherein the first inlet of the vortex assembly will direct fluid into the vortex chamber primarily tangentially.
166. An apparatus as in claim 165 wherein the second inlet of the vortex assembly will direct fluid into the vortex chamber primarily radially.
167, An apparatus as in claim 152 wherein the vortex chamber comprises a cylindrical
vortex chamber.
! 68. An apparatus as in claim 152 further comprising a fluid amplifier system interposed between the fluid ratio system and the pathway dependent resistance system and in fluid communication with both.
169. An apparatus as in claim 168 wherein the fluid amplifier system comprises a proportional amplifier.
170. An apparatus as in claim 168 wherein the fluid amplifier system comprises a bistable amplifier.
171. An apparatus as in claim 168 wherein the fluid ratio system further comprises a primary flow passageway, the primary flow passageway in fluid communication with the fluid amplifier system.
172. An apparatus as in claim 171 wherein the first and second passageways of the flow ratio control system will direct flow from the primary passageway.
173. An apparatus as in claim 152 further comprising multiple fluid amplifier systems interposed between the fluid ratio system and the pathway dependent resistance system, the fluid amplifier systems arranged in series.
174. An apparatus as in claim 154, wherein the first passageway of the fluid ratio control system will provide a lesser increase in resistance than the second passageway to fluid flow as the flow rate increases.
175. An apparatus as in claim 154, wherein the flow ratio control system comprises a bistable switch.
176. An apparatus as in claim 154, wherein the second passageway of the fluid ratio system will provide less resistance to fluid flow than the first passageway when the fluid flow rate is lower than a target flow rate.
177. An apparatus as in claim 154, wherein the second passageway of the fluid ratio system provides substantially constant resistance to fluid flow regardless of changes in fluid flow rate.
178. An apparatus as in claim 155, wherein the first passageway of the fluid ratio control is more density-dependent than the second passageway.
179. An apparatus as in claim 178, wherein the second passageway will provide substantially constant resistance to fluid flow as the density changes.
180. An apparatus as in claim 154, wherein the second passageway of the fluid ratio system will provide less resistance to fluid flow than the first passageway when the fluid density is higher than a target density.
181. An apparatus as in claim 152 wherein the flow control system is positioned in an oilfield tubular for positioning downhole in a wellbore extending through a subterranean formation.
182. An apparatus as in claim 181, wherein the oilfield tubular has an interior passageway in fluid communication with the flow ratio control system.
183. An apparatus as in claim 182. wherein formation fluid will flow from the formation into the tubular interior passageway.
184. An apparatus as in claim 181, wherein the flow control system is for controlling production fluid flow and wherein the apparatus selects oil production over natural gas production.
185. An apparatus as in claim 181, wherein the flow control system is for controlling production fluid flow and wherein the apparatus selects natural gas production over water production.
186. An apparatus as in claim 181, wherein the flow control system is for controlling production fluid flow and wherein the apparatus selects oil production over water production.
187. An apparatus as in claim 184, wherein the flow control system will provide higher resistance to flow as the composition of the formation fluid changes to a higher percentage of natural gas.
188. An apparatus as in claim 181, further comprising a plurality of flow control systems.
189. An apparatus as in claim 181, the flow control system for controlling injection of injection fluid from the oilfield tubular into the formation.
190. An apparatus as in claim 189, wherein the flow control system selects injection of steam over injection of water.
191. An apparatus as in claim 181, wherein the flow control system is for controlling flow of cementing fluid from the exterior of the oilfield tubular to the interior of the oilfield tubular during reverse cementing.
192. An apparatus as in claim 191, wherein the flow control system will provide higher resistance to flow of cementing fluid as the composition of the cementing fluid changes to a higher viscosity.
193. An apparatus as in claim 191, wherein the flow control system will provide higher resistance to flow of cementing fluid as the composition of the cementing fluid changes to a higher density.
194. An apparatus as in claim 191, wherein the flow control system will provide higher resistance to flow of cementing fluid as the composition of the cementing fluid changes to a higher flow rate.
195, An apparatus as in claim 191, further comprising a movable plug mounted in an interior passageway of the oilfield tubular and operable to restrict fluid flow into the interior passageway.
196. Art apparatus as in claim 191, wherein the flow ratio control system and pathway
dependent resistance system are positioned within the movable plug.
197. An apparatus as in claim 181, further comprising a screen assembly for sand control.
198. An apparatus as in claim 181, further comprising an inflow control device in fluid communication with the flow ratio control system.
199. An apparatus as in claim 181, further comprising a plurality of flow control systems spaced along the wellbore.
200. An apparatus as in claim 199, wherein the plurality of flow control systems are positioned in a production string, the production string for extending through the wellbore along a production 2one of the formation.