DOWNHOLE FLUID FLOW CONTROL SYSTEM HAVING A FLUIDIC MODULE
WITH A BRIDGE NETWORK AND METHOD FOR USE OF SAME
TECHNICAL FIELD OF THE INVENTION
[OOOl] This invention relates, in general, to equipment utilized in conjunction with
operations performed in subterranean wells and, in particular, to a downhole fluid flow
control system and method that are operable to control the inflow of formation fluids and the
10 outflow of injection fluids with a fluidic module having a bridge network.
BACKGROUND OF THE INVENTION
[0002] Without limiting the scope of the present invention, its background will be
described with reference to producing fluid from a hydrocarbon bearing subterranean
15 formation, as an example.
[0003] During the completion of a well that traverses a hydrocarbon bearing
subterranean formation, production tubing and various completion equipment are installed in
the well to enable safe and efficient production of the formation fluids. For example, to
prevent the production of particulate material from an unconsolidated or loosely consolidated
20 subterranean formation, certain completions include one or more sand control screen
assemblies positioned proximate the desired production interval or intervals. In other
completions, to control the flowrate of production fluids into the production tubing, it is
common practice to install one or more flow control devices within the tubing string.
[0004] Attempts have been made to utilize fluid flow control devices within
25 completions requiring sand control. For example, in certain sand control screen assemblies,
after production fluids flow through the filter medium, the fluids are directed into a flow
control section. The flow control section may include one or more flow control components
such as flow tubes, nozzles, labyrinths or the like. Typically, the production flowrate through
these flow control screens is fixed prior to installation by the number and design of the flow
3 0 control components.
[0005] It has been found, however, that due to changes in formation pressure and
changes in formation fluid composition over the life of the well, it may be desirable to adjust
the flow control characteristics of the flow control sections. In addition, for certain
completions, such as long horizontal completions having numerous production intervals, it
may be desirable to independently control the inflow of production fluids into each of the
production intervals. Further, in some completions, it would be desirable to adjust the flow
control characteristics of the flow control sections without the requirement for well
intervention.
5 [0006] Accordingly, a need has arisen for a flow control screen that is operable to
control the inflow of formation fluids in a completion requiring sand control. A need has also
arisen for flow control screens that are operable to independently control the inflow of
production fluids from multiple production intervals. Further, a need has arisen for such flow
control screens that are operable to control the inflow of production fluids without the
10 requirement for well intervention as the composition of the fluids produced into specific
intervals changes over time.
SUMMARY OF THE INVENTION
[0007] The present invention disclosed herein comprises a downhole fluid flow control
15 system for controlling fluid production in completions requiring sand control. In addition,
the downhole fluid flow control system of the present invention is operable to independently
control the inflow of production fluids into multiple production intervals without the
requirement for well intervention as the composition of the fluids produced into specific
intervals changes over time.
20 [0008] In one aspect, the present invention is directed to a downhole fluid flow control
system. The downhole fluid flow control system includes a fluidic module having a bridge
network with first and second branch fluid pathways each including at least one fluid flow
resistor and a pressure output terminal. The pressure difference between the pressure output
terminals of the first and second branch fluid pathways is operable to control fluid flow
25 through the fluidic module.
[0009] In one embodiment, the first and second branch fluid pathways each include at
least two fluid flow resistors. In this embodiment, the pressure output terminals of each
branch fluid pathway may be positioned between the two fluid flow resistors. Also, in this
embodiment, the two fluid flow resistors of each branch fluid pathway may have different
30 responses to a fluid property such as fluid viscosity, fluid density, fluid composition or the
like. In certain embodiments, the first and second branch fluid pathways may each have a
common fluid inlet and a common fluid outlet with a main fluid pathway. In such
embodiments, the fluid flowrate ratio between the main fluid pathway and the branch fluid
pathways may be between about 5 to 1 and about 20 to 1 and is preferably greater than 10 to
1.
[OOlO] In one embodiment, the fluidic module may include a valve having first and
second positions. In the first position, the valve is operable to allow fluid flow through the
5 main fluid pathway. In the second position, the valve is operable to prevent fluid flow
through the main fluid pathway. In this embodiment, the pressure difference between the
pressure output terminals of the first and second branch fluid pathways is operable to shift the
valve between the first and second positions. In some embodiments, the fluidic module may
have an injection mode wherein the pressure difference between the pressure output terminals
10 of the first and second branch fluid pathways created by an outflow of injection fluid shifts
the valve to open the main fluid pathway and a production mode wherein the pressure
difference between the pressure output terminals of the first and second branch fluid
pathways created by an inflow of production fluid shifts the valve to close the main fluid
pathway.
15 [OOll] In other embodiments, the fluidic module may have a first production mode
wherein the pressure difference between the pressure output terminals of the first and second
branch fluid pathways created by an inflow of a desired fluid shifts the valve to open the
main fluid pathway and a second production mode wherein the pressure difference between
the pressure output terminals of the first and second branch fluid pathways created by an
20 inflow of an undesired fluid shifts the valve to close the main fluid pathway. In any of these
embodiments, the fluid flow resistors may be selected from the group consisting of nozzles,
vortex chambers, flow tubes, fluid selectors and matrix chambers.
[0012] In another aspect, the present invention is directed to a flow control screen. The
flow control screen includes a base pipe with an internal passageway, a blank pipe section
25 and a perforated section. A filter medium is positioned around the blank pipe section of the
base pipe. A housing is positioned around the base pipe defining a fluid flow path between
the filter medium and the internal passageway. At least one fluidic module is disposed within
the fluid flow path. The fluidic module has a bridge network with first and second branch
fluid pathways each including at least one fluid flow resistor and a pressure output terminal
30 such that a pressure difference between the pressure output terminals of the first and second
branch fluid pathways is operable to control fluid flow through the fluidic module.
[0013] In a further aspect, the present invention is directed to a downhole fluid flow
control system. The downhole fluid flow control system includes a fluidic module having a
main fluid pathway, a valve and a bridge network. The valve has a first position wherein
fluid flow through the main fluid pathway is allowed and a second position wherein fluid
flow through the main fluid pathway is restricted. The bridge network has first and second
branch fluid pathways each have a common fluid inlet and a common fluid outlet with the
5 main fluid pathway and each including two fluid flow resistors with a pressure output
terminal positioned therebetween. A pressure difference between the pressure output
terminals of the first and second branch fluid pathways is operable to shift the valve between
the first and second positions.
[0014] In yet another aspect, the present invention is directed to a downhole fluid flow
10 control method. The method includes positioning a fluid flow control system at a target
location downhole, the fluid flow control system including a fluidic module having a main
fluid pathway, a valve and a bridge network with first and second branch fluid pathways each
having a common fluid inlet and a common fluid outlet with the main fluid pathway and each
including two fluid flow resistors with a pressure output terminal positioned therebetween;
15 producing a desired fluid through the fluidic module; generating a first pressure difference
between the pressure output terminals of the first and second branch fluid pathways that
biases the valve toward a first position wherein fluid flow through the main fluid pathway is
allowed; producing an undesired fluid through the fluidic module; and generating a second
pressure difference between the pressure output terminals of the first and second branch fluid
20 pathways that shifts the valve from the first position to a second position wherein fluid flow
through the main fluid pathway is restricted.
[0015] The method may also include biasing the valve toward the first position
responsive to producing a formation fluid containing at least a predetermined amount of the
desired fluid, shifting the valve from the first position to the second position responsive to
25 producing a formation fluid containing at least a predetermined amount of the undesired fluid
or sending a signal to the surface indicating the valve has shifted from the first position to the
second position.
BRIEF DESCRIPTION OF THE DRAWINGS
30 [0016] 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:
[0017] Figure 1 is a schematic illustration of a well system operating a plurality of flow
control screens according to an embodiment of the present invention;
[0018] Figures 2A-2B are quarter sectional views of successive axial sections of a
downhole fluid flow control system embodied in a flow control screen according to an
5 embodiment of the present invention;
[0019] Figure 3 is a top view of the flow control section of a flow control screen with
the outer housing removed according to an embodiment of the present invention;
[0020] Figures 4A-B are schematic illustrations of a fluidic module according to an
embodiment of the present invention in first and second operating configurations;
10 [0021] Figures 5A-B are schematic illustrations of a fluidic module according to an
embodiment of the present invention in first and second operating configurations;
[0022] Figures 6A-B are schematic illustrations of a fluidic module according to an
embodiment of the present invention in first and second operating configurations; and
[0023] Figures 7A-F are schematic illustrations of fluid flow resistors for use in a
15 fluidic module according to various embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] While the making and using of various embodiments of the present invention
are discussed in detail below, it should be appreciated that the present invention provides
20 many applicable inventive concepts which can be embodied in a wide variety of specific
contexts. The specific embodiments discussed herein are merely illustrative of specific ways
to make and use the invention, and do not delimit the scope of the present invention.
[0025] Referring initially to figure 1, therein is depicted a well system including a
plurality of downhole fluid flow control systems positioned in flow control screens
25 embodying principles of the present invention that is schematically illustrated and generally
designated 10. In the illustrated embodiment, a wellbore 12 extends through the various
earth strata. Wellbore 12 has a substantially vertical section 14, the upper portion of which
has cemented therein a casing string 16. Wellbore 12 also has a substantially horizontal
section 18 that extends through a hydrocarbon bearing subterranean formation 20. As
30 illustrated, substantially horizontal section 18 of wellbore 12 is open hole.
[0026] Positioned within wellbore 12 and extending from the surface is a tubing string
22. Tubing string 22 provides a conduit for formation fluids to travel from formation 20 to
the surface and for injection fluids to travel from the surface to formation 20. At its lower
end, tubing string 22 is coupled to a completions string that has been installed in wellbore 12
and divides the completion interval into various production intervals adjacent to formation
20. The completion string includes a plurality of flow control screens 24, each of which is
positioned between a pair of annular barriers depicted as packers 26 that provides a fluid seal
5 between the completion string and wellbore 12, thereby defining the production intervals. In
the illustrated embodiment, flow control screens 24 serve the function of filtering particulate
matter out of the production fluid stream. Each flow control screens 24 also has a flow
control section that is operable to control fluid flow therethrough.
[0027] For example, the flow control sections may be operable to control flow of a
10 production fluid stream during the production phase of well operations. Alternatively or
additionally, the flow control sections may be operable to control the flow of an injection
fluid stream during a treatment phase of well operations. As explained in greater detail
below, the flow control sections preferably control the inflow of production fluids over the
life of the well into each production interval without the requirement for well intervention as
15 the composition of the fluids produced into specific intervals changes over time in order to
maximize production of a desired fluid such as oil and minimize production of an undesired
fluid such as water or gas.
[0028] Even though figure 1 depicts the flow control screens of the present invention in
an open hole environment, it should be understood by those skilled in the art that the present
20 invention is equally well suited for use in cased wells. Also, even though figure 1 depicts one
flow control screen in each production interval, it should be understood by those skilled in
the art that any number of flow control screens of the present invention may be deployed
within a production interval without departing from the principles of the present invention.
In addition, even though figure 1 depicts the flow control screens of the present invention in a
25 horizontal section of the wellbore, it should be understood by those skilled in the art that the
present invention is equally well suited for use in wells having other directional
configurations including vertical wells, deviated wells, slanted wells, multilateral wells and
the like. Accordingly, it should be understood by those skilled in the art that the use of
directional terms such as above, below, upper, lower, upward, downward, left, right, uphole,
30 downhole and the like are used in 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, the uphole
direction being toward the surface of the well and the downhole direction being toward the
toe of the well. Further, even though figure 1 depicts the flow control components associated
with flow control screens in a tubular string, it should be understood by those skilled in the
art that the flow control components of the present invention need not be associated with a
flow control screen or be deployed as part of the tubular string. For example, one or more
5 flow control components may be deployed and removably inserted into the center of the
tubing string or side pockets of the tubing string.
[0029] Referring next to figures 2A-2B, therein is depicted successive axial sections of
a flow control screen according to the present invention that is representatively illustrated and
generally designated 100. Flow control screen 100 may be suitably coupled to other similar
10 flow control screens, production packers, locating nipples, production tubulars or other
downhole tools to form a completions string as described above. Flow control screen 100
includes a base pipe 102 that has a blank pipe section 104 and a perforated section 106
including a plurality of production ports 108. Positioned around an uphole portion of blank
pipe section 104 is a screen element or filter medium 112, such as a wire wrap screen, a
15 woven wire mesh screen, a prepacked screen or the like, with or without an outer shroud
positioned therearound, designed to allow fluids to flow therethrough but prevent particulate
matter of a predetermined size from flowing therethrough. It will be understood, however, by
those skilled in the art that the present invention does not need to have a filter medium
associated therewith, accordingly, the exact design of the filter medium is not critical to the
20 present invention.
[0030] Positioned downhole of filter medium 112 is a screen interface housing 114 that
forms an annulus 1 16 with base pipe 102. Securably connected to the downhole end of
screen interface housing 114 is a flow control housing 118. At its downhole end, flow
control housing 11 8 is securably connected to a support assembly 120 which is securably
25 coupled to base pipe 102. The various connections of the components of flow control screen
100 may be made in any suitable fashion including welding, threading and the like as well as
through the use of fasteners such as pins, set screws and the like. Positioned between support
assembly 120 and flow control housing 118 are a plurality of fluidic modules 122, only one
of which is visible in figure 2B. In the illustrated embodiment, fluidic modules 122 are
30 circumferentially distributed about base pipe 102 at one hundred and twenty degree intervals
such that three fluidic modules 122 are provided. Even though a particular arrangement of
fluidic modules 122 has been described, it should be understood by those skilled in the art
that other numbers and arrangements of fluidic modules 122 may be used. For example,
either a greater or lesser number of circumferentially distributed flow control components at
uniform or nonuniform intervals may be used. Additionally or alternatively, fluidic modules
122 may be longitudinally distributed along base pipe 102.
[003 11 As discussed in greater detail below, fluidic modules 122 may be operable to
5 control the flow of fluid in either direction therethrough. For example, during the production
phase of well operations, fluid flows from the formation into the production tubing through
fluid flow control screen 100. The production fluid, after being filtered by filter medium 112,
if present, flows into annulus 116. The fluid then travels into an annular region 130 between
base pipe 102 and flow control housing 118 before entering the flow control section as
10 further described below. The fluid then enters one or more inlets of fluidic modules 122
where the desired flow operation occurs depending upon the composition of the produced
fluid. For example, if a desired fluid is produced, flow through fluidic modules 122 is
allowed. If an undesired fluid is produced, flow through fluidic modules 122 is restricted or
substantially prevented. In the case of producing a desired fluid, the fluid is discharged
15 through opening 108 to interior flow path 132 of base pipe 102 for production to the surface.
[0032] As another example, during the treatment phase of well operations, a treatment
fluid may be pumped downhole from the surface in interior flow path 132 of base pipe 102.
As it is typically desirable to inject the treatment fluid at a much higher flowrate than the
expected production flowrate, the present invention enables interventionless opening of
20 injection pathways which will subsequently close interventionlessly upon commencement of
production. In this case, the treatment fluid enters the fluidic modules 122 through openings
108 where the desired flow operation occurs and the injection pathways are opened. The
fluid then travels into annular region 130 between base pipe 102 and flow control housing
1 18 before entering annulus 1 16 and passing through filter medium 1 12 for injection into the
25 surrounding formation. When production begins, and fluid enters fluidic modules 122 from
annular region 130, the desired flow operation occurs and the injection pathways are closed.
In certain embodiments, fluidic modules 122 may be used to bypass filter medium 112
entirely during injection operations.
[0033] Referring next to figure 3, a flow control section of flow control screen 100 is
30 representatively illustrated. In the illustrated section, support assembly 120 is securably
coupled to base pipe 102. Support assembly 120 is operable to receive and support three
fluidic modules 122. The illustrated fluidic modules 122 may be formed from any number of
components and may include a variety of fluid flow resistors as described in greater detail
below. Support assembly 120 is positioned about base pipe 102 such that fluid discharged
from fluidic modules 122 during production will be circumferentially and longitudinally
aligned with the openings 108 (see figure 2B) of base pipe 102. Support assembly 120
includes a plurality of channels for directing fluid flow between fluidic modules 122 and
5 annular region 130. Specifically, support assembly 120 includes a plurality of longitudinal
channels 134 and a plurality of circumferential channels 136. Together, longitudinal
channels 134 and circumferential channels 136 provide a pathway for fluid flow between
openings 138 of fluidic modules 122 and annular region 130.
[0034] Referring next to figures 4A-4B, therein is depicted a schematic illustration of a
10 fluidic module of the present invention in its open and closed operating positions that is
generally designated 150. Fluidic module 150 includes a main fluid pathway 152 having an
inlet 154 and an outlet 156. Main fluid pathway 152 provides the primary flow path for fluid
transfer through fluidic module 150. In the illustrated embodiment, a pair of fluid flow
resistors 158, 160 are positioned within main fluid pathway 152. Fluid flow resistors 158,
15 160 may be of any suitable type, such as those described below, and are used to create a
desired pressure drop in the fluid passing through main fluid pathway 152, which assures
proper operation of fluidic module 150.
[0035] A valve 162 is positioned relative to main fluid pathway 152 such that valve 162
has a first position wherein fluid flow through main fluid pathway 152 is allowed, as best
20 seen in figure 4A, and a second position wherein fluid flow through main fluid pathway 152
is prevented, as best seen in figure 4B. In the illustrated embodiment, valve 162 is a pressure
operated shuttle valve. Even though valve 162 is depicted as a shuttle valve, those skilled in
the art will understand that other types of pressure operated valves could alternatively be used
in a fluidic module of the present invention including sliding sleeves, ball valves, flapper
25 valves or the like. Also, even though valve 162 is depicted as having two positions; namely
opened and closed positions, those skilled in the art will understand that valves operating in a
fluidic module of the present invention could alternatively have two opened positions with
different levels of fluid choking or more than two positions such as an open position, one or
more choking positions and a closed position.
30 [0036] Fluidic module 150 includes a bridge network having two branch fluid pathways
163, 164. In the illustrated embodiment, branch fluid pathway 163 has an inlet 166 from
main fluid pathway 152. Likewise, branch fluid pathway 164 has an inlet 168 from main
fluid pathway 152. Branch fluid pathway 163 has an outlet 170 into main fluid pathway 152.
Similarly, branch fluid pathway 164 has an outlet 172 into main fluid pathway 152. As
depicted, branch fluid pathways 163, 164 are in fluid communication with main fluid
pathway 152, however, those skilled in the art will recognize that branch fluid pathways 163,
164 could alternatively be tapped along a fluid pathway other than main fluid pathway 152 or
5 be tapped directly to one or more inlets and outlets of fluidic module 150. In any such
configurations, branch fluid pathways 163, 164 will be considered to have common fluid
inlets and common fluid outlets with the main fluid pathway so long as branch fluid pathways
163, 164 and main fluid pathway 152 directly or indirectly share the same pressure sources,
such as wellbore pressure and tubing pressure, or are otherwise fluidically connected. It
10 should be noted that the fluid flowrate through main fluid pathway 152 is typically much
greater than the flowrate through branch fluid pathways 163, 164. For example, the ratio in
the fluid flowrate between main fluid pathway 152 and branch fluid pathways 163, 164 may
be between about 5 to 1 and about 20 to 1 and is preferably greater than 10 to 1.
[0037] Branch fluid pathway 163 has two fluid flow resistors 174, 176 positioned in
15 series with a pressure output terminal 178 positioned therebetween. Likewise, branch fluid
pathway 164 has two fluid flow resistors 180, 182 positioned in series with a pressure output
terminal 184 positioned therebetween. Pressure from pressure output terminal 178 is routed
to valve 162 via fluid pathway 186. Pressure from pressure output terminal 184 is routed to
valve 162 via fluid pathway 188. As such, if the pressure at pressure output terminal 184 is
20 higher than the pressure at pressure output terminal 178, valve 162 is biased to the open
position, as best seen in figure 4A. Alternatively, if the pressure at pressure output terminal
178 is higher than the pressure at pressure output terminal 184, valve 162 is biased to the
closed position, as best seen in figure 4B.
[0038] The pressure difference between pressure output terminals 178, 184 is created
25 due to differences in flow resistance and associated pressure drops in the various fluid flow
resistors 174, 176, 180, 182. As shown, the bridge network can be described as two parallel
branches each having two fluid flow resistors in series with a pressure output terminal
therebetween. This configuration simulates the common Wheatstone bridge circuit. With
this configuration, fluid flow resistors 174, 176, 180, 182 can be selected such that the flow
30 of a desired fluid such as oil through fluidic module 150 generates a differential pressure
between pressure output terminals 178, 184 that biases valve 162 to the open position and the
flow of an undesired fluid such as water or gas through fluidic module 150 generates a
differential pressure between pressure output terminals 178, 184 that biases valve 162 to the
closed position.
[0039] For example, fluid flow resistors 174, 176, 180, 182 can be selected such that
their flow resistance will change or be dependent upon a property of the fluid flowing
5 therethrough such as fluid viscosity, fluid density, fluid composition, fluid velocity, fluid
pressure or the like. In the example discussed above wherein oil is the desired fluid and
water or gas is the undesired fluid, fluid flow resistors 174, 182 may be nozzles, such as that
depicted in figure 7A, and fluid flow resistors 176, 178 may be vortex chambers, such as that
depicted in figure 7B. In this configuration, when the desired fluid, oil, flows through branch
10 fluid pathway 163, it experience a greater pressure drop in fluid flow resistor 174, a nozzle,
than in fluid flow resistor 176, a vortex chamber. Likewise, as the desired fluid flows
through branch fluid pathway 164, it experiences a lower pressure drop in fluid flow resistor
180, a vortex chamber, than in fluid flow resistor 182, a nozzle. As the total pressure drop
across each branch fluid pathway 163, 164 must be the same due to the common fluid inlets
15 and common fluid outlets, the pressure at pressure output terminals 178, 184 is different. In
this case, the pressure at pressure output terminal 178 is less than the pressure at pressure
output terminal 184, thus biasing valve 162 to the open position shown in figure 4A.
[0040] Also, in this configuration, when the undesired fluid, water or gas, flows
through branch fluid pathway 163, it experiences a lower pressure drop in fluid flow resistor
20 174, a nozzle, than in fluid flow resistor 176, a vortex chamber. Likewise, as the undesired
fluid flows through branch fluid pathway 164, it experiences a greater pressure drop in fluid
flow resistor 180, a vortex chamber, than in fluid flow resistor 182, a nozzle. As the total
pressure drop across each branch fluid pathway 163, 164 must be the same, due to the
common fluid inlets and common fluid outlets, the pressure at pressure output terminals 178,
25 184 is different. In this case, the pressure at pressure output terminal 178 is greater than the
pressure at pressure output terminal 184, thus biasing valve 163 to the closed position shown
in figure 4B.
[0041] While particular fluid flow resistors have been described as being positioned in
fluidic module 150 as fluid flow resistors 174, 176, 180, 182, it is to be clearly understood
30 that other types and combinations of fluid flow resistors may be used to achieve fluid flow
control through fluidic module 150. For example, if oil is the desired fluid and water is the
undesired fluid, fluid flow resistors 174, 182 may include flow tubes, such as that depicted in
figure 7C or other tortuous path flow resistors, and fluid flow resistors 176, 178 may be
vortex chambers, such as that depicted in figure 7B or fluidic diodes having other
configurations. In another example, if oil is the desired fluid and gas is the undesired fluid,
fluid flow resistors 174, 182 may be matrix chambers, such as that depicted in figure 7D
wherein a chamber contain beads or other fluid flow resisting filler material, and fluid flow
5 resistors 176, 178 may be vortex chambers, such as that depicted in figure 7B. In yet another
example, if oil or gas is the desired fluid and water is the undesired fluid, fluid flow resistors
174, 182 may be fluid selectors that include a material that swells when it comes in contact
with hydrocarbons, such as that depicted in figures 7E, and fluid flow resistors 176, 178 may
be fluid selectors that include a material that swells when it comes in contact with water, such
10 as that depicted in figure 7F. Alternatively, fluid flow resistors of the present invention could
include materials that are swellable in response to other stimulants such as pH, ionic
concentration or the like.
[0042] Even though figures 4A-4B have been described as having the same types of
fluid flow resistors in each branch fluid pathway but in reverse order, it should be understood
15 by those skilled in the art that other configurations of fluid flow resistors that create the
desired pressure difference between the pressure output terminals are possible and are
considered within the scope of the present invention. Also, even though figures 4A-4B have
been described as having two fluid flow resistors in each branch fluid pathway, it should be
understood by those skilled in the art that other configurations having more or less than two
20 fluid flow resistors that create the desired pressure difference between the pressure output
terminals are possible and are considered within the scope of the present invention.
[0043] Referring next to figures 5A-5B, therein is depicted a schematic illustration of a
fluidic module of the present invention in its open and closed operating positions that is
generally designated 250. Fluidic module 250 includes a main fluid pathway 252 having an
25 inlet 254 and an outlet 256. Main fluid pathway 252 provides the primary flow path for fluid
transfer through fluidic module 250. In the illustrated embodiment, a pair of fluid flow
resistors 258, 260 are positioned within main fluid pathway 252. A valve 262 is positioned
relative to main fluid pathway 252 such that valve 262 has a first position wherein fluid flow
through main fluid pathway 252 is allowed, as best seen in figure 5A, and a second position
30 wherein fluid flow through main fluid pathway 252 is prevented, as best seen in figure 5B. In
the illustrated embodiment, valve 262 is a pressure operated shuttle valve that is biased to the
open position by a spring 264.
[0044] Fluidic module 250 includes a bridge network having two branch fluid pathways
266, 268. In the illustrated embodiment, branch fluid pathway 266 has an inlet 270 from
main fluid pathway 252. Likewise, branch fluid pathway 268 has an inlet 272 from main
fluid pathway 252. Branch fluid pathway 266 has an outlet 274 into main fluid pathway 252.
5 Similarly, branch fluid pathway 268 has an outlet 276 into main fluid pathway 252. Branch
fluid pathway 266 has two fluid flow resistors 278, 280 positioned in series with a pressure
output terminal 282 positioned therebetween. Branch fluid pathway 268 has a pressure
output terminal 284. Pressure from pressure output terminal 282 is routed to valve 262 via
fluid pathway 286. Pressure from pressure output terminal 284 is routed to valve 262 via
10 fluid pathway 288. As such, if the combination of the spring force and pressure force
generated from pressure output terminal 284 is higher than the pressure force generated from
pressure output terminal 282, valve 262 is biased to the open position, as best seen in figure
5A. Alternatively, if the pressure force generated from pressure output terminal 282, is
higher than the combination of the spring force and pressure force generated from pressure
15 output terminal 284, valve 262 is biased to the closed position, as best seen in figure 5B.
[0045] The pressure difference between pressure output terminals 282, 284 is created
due to differences in flow resistance and associated pressure drops in the fluid flow resistors
278, 280. With this configuration, fluid flow resistors 278, 280 can be selected such that the
flow of a desired fluid such as oil through fluidic module 250 generates a differential pressure
20 between pressure output terminals 282, 284 that together with the spring force biases valve
262 to the open position shown in figure 5A. Likewise, the flow of an undesired fluid such
as water or gas through fluidic module 250 generates a differential pressure between pressure
output terminals 282, 284 that is sufficient to overcome the spring force and biases valve 262
to the closed position shown in figure 5B.
25 [0046] Referring next to figures 6A-6B, therein is depicted a schematic illustration of a
fluidic module of the present invention in its open and closed operating positions that is
generally designated 350. Fluidic module 350 includes a main fluid pathway 352 has a pair
of inletloutlet ports 354, 356. Main fluid pathway 352 provides the primary flow path for
fluid transfer through fluidic module 350. In the illustrated embodiment, a pair of fluid flow
30 resistors 358, 360 are positioned within main fluid pathway 352. A valve 362 is positioned
relative to main fluid pathway 352 such that valve 362 has a first position wherein fluid flow
through main fluid pathway 352 is allowed, as best seen in figure 6A, and a second position
wherein fluid flow through main fluid pathway 352 is prevented, as best seen in figure 6B. In
the illustrated embodiment, valve 362 is a pressure operated shuttle valve.
[0047] Fluidic module 350 includes a bridge network having two branch fluid pathways
366, 368. In the illustrated embodiment, branch fluid pathway 366 has a pair of inletloutlet
5 ports 370, 374 with main fluid pathway 352. Likewise, branch fluid pathway 368 has a pair
of inletloutlet ports 372, 376 with main fluid pathway 352. Branch fluid pathway 366 has a
fluid flow resistor 378 and a pressure output terminal 380. Branch fluid pathway 368 has a
fluid flow resistor 382 and a pressure output terminal 384. Pressure from pressure output
terminal 380 is routed to valve 362 via fluid pathway 386. Pressure from pressure output
10 terminal 384 is routed to valve 362 via fluid pathway 388. As such, if the pressure from
pressure output terminal 384 is higher than the pressure from pressure output terminal 380,
valve 362 is biased to the open position, as best seen in figure 6A. Alternatively, if the
pressure from pressure output terminal 380 is higher than the pressure from pressure output
terminal 384, valve 362 is biased to the closed position, as best seen in figure 6B.
15 [0048] The pressure difference between pressure output terminals 380, 384 is created
due to the flow resistance and associated pressure drops created by fluid flow resistors 378,
382. With this configuration, the injection of fluids from the interior of the tubing string into
the formation through fluidic module 350 as indicated by the arrows in figure 6A generates a
differential pressure between pressure output terminals 380, 384 that biases valve 362 to the
20 open position. During production, however, formation fluid flowing into the interior of the
tubing string through fluidic module 350 as indicated by the arrows in figure 6B generates a
differential pressure between pressure output terminals 380, 384 that biases valve 362 to the
closed position. In this manner, the flow rate of the injection fluids through fluidic module
350 can be significantly higher than the flow rate of formation fluid during production.
25 [0049] As should be understood by those skilled in the art, the use of a combination of
different fluid flow resistors in series on two separate branches of a parallel bridge network
enables a pressure differential to be created between selected locations across the bridge
network when fluids travel therethrough. The differential pressure may then be used to do
work downhole such as shifting a valve as described above.
30 [0050] In addition, while the fluidic modules of the present invention have been
described as inflow control devices for production fluids and outflow control devices for
injection fluids, it should be understood by those skilled in the art that the fluidic modules of
the present invention could alternatively operate as actuators for other downhole tools
wherein the force required to actuate the other downhole tools may be significant. In such
embodiments, fluid flow through the branch fluid pathways of the fluidic module may be
used to shift a valve initially blocking the main fluid pathway of the fluidic module. Once
the main fluid pathway is open, fluid flow through the main fluid pathway may be used to
5 perform work on the other downhole tool.
[0051] In certain installations, such as long horizontal completions having numerous
production intervals, it may be desirable to send a signal to the surface when a particular
fluidic module of the present invention has been actuated. If a fluidic module of the present
invention is shifted from an open configuration to a closed configuration due to a change in
10 the composition of the production fluid from predominately oil to predominantly water, for
example, the actuation of a fluidic module could also trigger a signal that is sent to the
surface. In one implementation, the actuation of each fluidic module could trigger the release
of a unique tracer material that is carried to the surface with the production fluid. Upon
reaching the surface, the tracer material is identified and associated with the fluidic module
15 that triggered its release such that the location of the water breakthrough can be determined.
[0052] 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
20 the description. It is, therefore, intended that the appended claims encompass any such
modifications or embodiments.

What is claimed is:
1. A downhole fluid flow control system comprising:
a fluidic module having a bridge network with first and second branch fluid pathways
each including at least one fluid flow resistor and a pressure output terminal;
5 wherein a pressure difference between the pressure output terminals of the first and
second branch fluid pathways is operable to control fluid flow through the fluidic module.
2. The flow control system as recited in claim 1 wherein the first and second
branch fluid pathways each include at least two fluid flow resistors.
10
3. The flow control system as recited in claim 2 wherein the pressure output
terminal of each branch fluid pathway is positioned between the two fluid flow resistors.
4. The flow control system as recited in claim 2 wherein the two fluid flow
15 resistors of each branch fluid pathway have different responses to fluid viscosity.
5. The flow control system as recited in claim 2 wherein the two fluid flow
resistors of each branch fluid pathway have different responses to fluid density.
20 6. The flow control system as recited in claim 1 wherein the first and second
branch fluid pathways each have a common fluid inlet and a common fluid outlet with a main
fluid pathway.
7. The flow control system as recited in claim 6 wherein a fluid flowrate ratio
25 between the main fluid pathway and the branch fluid pathways is between about 5 to 1 and
about 20 to 1.
8. The flow control system as recited in claim 6 wherein a fluid flowrate ratio
between the main fluid pathway and the branch fluid pathways is greater than 10 to 1.
9. The flow control system as recited in claim 6 wherein the fluidic module
further comprises a valve having first and second positions, in the first position, the valve is
operable to allow fluid flow through the main fluid pathway, in the second position, the valve
is operable to prevent fluid flow through the main fluid pathway and wherein the pressure
5 difference between the pressure output terminals of the first and second branch fluid
pathways is operable to shift the valve between the first and second positions.
10. The flow control system as recited in claim 9 wherein the fluidic module has
an injection mode, wherein the pressure difference between the pressure output terminals of
10 the first and second branch fluid pathways created by an outflow of injection fluid shifts the
valve to open the main fluid pathway, and a production mode, wherein the pressure
difference between the pressure output terminals of the first and second branch fluid
pathways created by an inflow of production fluid shifts the valve to close the main fluid
pathway.
15
11. The flow control system as recited in claim 9 wherein the fluidic module has a
first production mode, wherein the pressure difference between the pressure output terminals
of the first and second branch fluid pathways created by an inflow of a desired fluid shifts the
valve to open the main fluid pathway, and a second production mode, wherein the pressure
20 difference between the pressure output terminals of the first and second branch fluid
pathways created by an inflow of an undesired fluid shifts the valve to close the main fluid
pathway.
12. The flow control system as recited in claim 1 wherein the fluid flow resistors
25 are selected from the group consisting of nozzles, vortex chambers, flow tubes, fluid selectors
and matrix chambers.
13. A flow control screen comprising:
a base pipe with an internal passageway;
a filter medium positioned around the base pipe;
a housing positioned around the base pipe defining a fluid flow path between the filter
5 medium and the internal passageway; and
at least one fluidic module disposed within the fluid flow path, the fluidic module
having a bridge network with first and second branch fluid pathways each including at least
one fluid flow resistor and a pressure output terminal such that a pressure difference between
the pressure output terminals of the first and second branch fluid pathways is operable to
10 control fluid flow through the fluidic module.
14. The flow control screen as recited in claim 13 wherein the fluid flow resistors
are selected from the group consisting of nozzles, vortex chambers, flow tubes, fluid selectors
and matrix chambers.
15
15. The flow control screen as recited in claim 13 wherein the first and second
branch fluid pathways each have a common fluid inlet and a common fluid outlet with a main
fluid pathway, wherein the first and second branch fluid pathways each include at least two
fluid flow resistors, wherein the pressure output terminal of each branch fluid pathway is
20 positioned between the two fluid flow resistors and wherein the fluidic module further
comprises a valve having a first position wherein fluid flow through the main fluid pathway
is allowed and a second position wherein fluid flow through the main fluid pathway is
restricted.
25 16. The flow control screen as recited in claim 15 wherein the fluidic module has
a first production mode, wherein the pressure difference between the pressure output
terminals of the first and second branch fluid pathways created by an inflow of a desired fluid
shifts the valve to open the main fluid pathway, and a second production mode, wherein the
pressure difference between the pressure output terminals of the first and second branch fluid
30 pathways created by an inflow of an undesired fluid shifts the valve to close the main fluid
pathway.
17. A downhole fluid flow control system comprising:
a fluidic module having a main fluid pathway, a valve having a first position wherein
fluid flow through the main fluid pathway is allowed and a second position wherein fluid
flow through the main fluid pathway is restricted, and a bridge network with first and second
5 branch fluid pathways each have a common fluid inlet and a common fluid outlet with the
main fluid pathway and each including two fluid flow resistors with a pressure output
terminal positioned therebetween;
wherein a pressure difference between the pressure output terminals of the first and
second branch fluid pathways is operable to shift the valve between the first and second
10 positions.
18. The flow control system as recited in claim 17 wherein the two fluid flow
resistors of each branch fluid pathway have different responses to fluid viscosity.
15 19. The flow control system as recited in claim 17 wherein the two fluid flow
resistors of each branch fluid pathway have different responses to fluid density.
20. The flow control system as recited in claim 17 wherein the fluidic module has
a first production mode, wherein the pressure difference between the pressure output
20 terminals of the first and second branch fluid pathways created by an inflow of a desired fluid
shifts the valve to open the main fluid pathway, and a second production mode, wherein the
pressure difference between the pressure output terminals of the first and second branch fluid
pathways created by an inflow of an undesired fluid shifts the valve to close the main fluid
pathway.
25
21. The flow control system as recited in claim 17 wherein the fluid flow resistors
are selected from the group consisting of nozzles, vortex chambers, flow tubes, fluid selectors
and matrix chambers.
22. A downhole fluid flow control method comprising:
positioning a fluid flow control system at a target location downhole, the fluid flow
control system including a fluidic module having a main fluid pathway, a valve and a bridge
network with first and second branch fluid pathways each having a common fluid inlet and a
5 common fluid outlet with the main fluid pathway and each including two fluid flow resistors
with a pressure output terminal positioned therebetween;
producing a desired fluid through the fluidic module;
generating a first pressure difference between the pressure output terminals of the first
and second branch fluid pathways that biases the valve toward a first position wherein fluid
10 flow through the main fluid pathway is allowed;
producing an undesired fluid through the fluidic module; and
generating a second pressure difference between the pressure output terminals of the
first and second branch fluid pathways that shifts the valve from the first position to a second
position wherein fluid flow through the main fluid pathway is restricted.
15
23. The method as recited in claim 22 wherein producing a desired fluid through
the fluidic module further comprises producing a formation fluid containing at least a
predetermined amount of the desired fluid.
20 24. The method as recited in claim 22 wherein producing an undesired fluid
through the fluidic module further comprises producing a formation fluid containing at least a
predetermined amount of the undesired fluid.
25. The method as recited in claim 22 further comprising sending a signal to the
25 surface indicating the valve has shifted from the first position to the second position.