[0001] The present invention generally relates to systems and methods
for regulating fluid flow, particularly within a subterranean formation, and, more
specifically, to rotational motion-inducing variable flow resistance systems
having a sidewall fluid outlet that allows the variable flow resistance systems to
be connected in series fluid communication with one another.
[0002] It can often be beneficial to regulate the flow of formation fluids
within a wellbore penetrating a subterranean formation. A variety of reasons or
purposes can necessitate such regulation including, for example, prevention of
water and/or gas coning, minimizing water and/or gas production, minimizing
sand production, maximizing oil production, balancing production from various
subterranean zones, equalizing pressure among various subterranean zones,
and/or the like.
[0003] Likewise, it can also be beneficial to regulate the flow of
injection fluids such as, for example, water, steam or gas, within a wellbore
penetrating a subterranean formation. Regulation of the flow of injection fluids
can be particularly useful, for example, to control the distribution of the injection
fluid within various subterranean zones and/or to prevent the introduction of
injection fluid into currently producing zones.
[0004] A number of different types of flow resistance systems have
been developed in order to meet the foregoing needs. Many of these flow
resistance systems are variable flow resistance systems that can restrict the
passage of some fluids more than others based upon one or more physical
property differences between the fluids. Illustrative physical properties of a fluid
that can determine its rate of passage through a variable flow resistance system
can include, for example, viscosity, velocity and density. Depending on the
type, composition and physical properties of a fluid or fluid mixture whose
passage is to be restricted, variable flow resistance systems can be configured
such that higher ratios of a desired fluid to an undesired fluid can flow through a
flow pathway containing the variable flow resistance system.
[0005] Rotational motion can be partici
restricting fluid flow within a variable flow resistance system. In variable flow
resistance systems capable of inducing rotational motion, a fluid composition
most often enters a chamber within the variable flow resistance system in such a
way that an undesired component of the fluid composition undergoes greater
rotational motion than does a desired component of the fluid composition. As a
result, the undesired component traverses a longer flow pathway than does the
desired component, and the undesired component's residence time within the
variable flow resistance system can be increased. Most often, the variable flow
resistance system is configured such that fluid exiting the variable flow
resistance system is discharged through a hole in the bottom of the chamber.
Although such an arrangement of the exit hole can be particularly effective for
inducing vortex-like rotational motion within a fluid, it significantly complicates
the coupling of multiple chambers to one another in linear series.
[0006] Multiple chambers having a bottom exit hole can be series
connected to form an operable variable flow resistance system, but the resulting
arrangement of the chambers can be inefficient in terms of space utilization. For
example, FIGURES 1A - 1C show side view schematics of several possible
arrangements of multiple chambers having a bottom exit hole that are in series
connection with one another. As shown in FIGURES 1A and IB, bottom exit hole
9 of chamber 5 within variable flow resistance systems 1 and 3 can particularly
lend itself to vertical (FIGURE 1A) or stepped-vertical (FIGURES IB)
arrangements of the chambers. In confined locales, such as, for example, within
a wellbore, such arrangements can prove problematic in terms of available space
utilization. As shown in FIGURE 1C, a substantially horizontal arrangement of
chambers having a bottom exit hole within variable flow resistance system 4 is
possible, at least in principle. However, the substantially horizontal arrangement
of chambers shown in FIGURE 1C can also prove problematic by requiring a
vertical movement of fluid during transit between adjacent chambers.
SUMMARY OF THE INVENTION
[0007] The present invention generally relates to systems and methods
for regulating fluid flow, particularly within a subterranean formation, and, more
specifically, to rotational motion-inducing variable flow resistance systems
having a sidewall fluid outlet that allows the variable flow resistance systems to
- QG u cat o with one another.
[0008] In some embodiments, the present
flow resistance system comprising : a chamber configured to induce rotational
motion of a fluid flowing therethrough; a fluid inlet coupled to the chamber; and
a fluid outlet coupled to the chamber that allows the fluid to exit through at least
a sidewall of the chamber.
[0009] In other embodiments, the present invention provides a variable
flow resistance system comprising : a plurality of chambers that are connected
in series fluid communication with one another, each chamber having a fluid
inlet and a fluid outlet coupled thereto; wherein at least some of the chambers
are configured to induce rotational motion of a fluid flowing therethrough; and
wherein the fluid outlets of at least some of the chambers are configured to
allow the fluid to exit through at least a sidewall of the chamber.
[0010] In still other embodiments, the present invention provides a
method comprising : installing a wellbore pipe in an uncompleted wellbore;
wherein the wellbore pipe comprises at least one variable flow resistance system
in fluid communication with the interior of the wellbore pipe, each variable flow
resistance system comprising : a plurality of chambers that are connected in
series fluid communication with one another, each chamber having a fluid inlet
and a fluid outlet coupled thereto; wherein at least some of the chambers are
configured to induce rotational motion of a fluid flowing therethrough; and
wherein the fluid outlets of at least some of the chambers are configured to
allow the fluid to exit through at least a sidewall of the chamber.
[0011] The features and advantages of the present invention will be
readily apparent to one having ordinary skill in the art upon a reading of the
description of the preferred embodiments that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The following figures are included to illustrate certain aspects of
the present invention, and should not be viewed as exclusive or preferred
embodiments. The subject matter disclosed is capable of considerable
modification, alteration, and equivalents in form and function, as will occur to
one having ordinary skill in the art and having the benefit of this disclosure.
[0013] FIGURES 1A - 1C show side view schematics of several possible
arrangements of multiple chambers having a bottom exit hole that are in series
connection with one another.
[0014] FIGURE 2 shows a partial cross-se
in which the variable flow resistance systems of the present disclosure can be
used.
[0015] FIGURE 3A shows a side view schematic of a variable flow
resistance system having a single chamber with a channel extending from the
bottom interior surface of the chamber though a sidewall of the chamber.
FIGURE 3B shows a cutaway top view schematic of a variable flow resistance
system having a single chamber with a channel extending from the bottom
interior surface of the chamber though a sidewall of the chamber. FIGURES 3C
and 3D show cutaway top view schematics of a variable flow resistance system
having multiple chambers coupled to one another in series. FIGURE 3E shows a
side view schematic of a variable flow resistance system having a single
chamber with a cone-shaped fluid exit extending from the bottom interior
surface of the chamber though a sidewall of the chamber.
[0016] FIGURES 4A and 4B show side view schematics of a variable
flow resistance system having a single chamber that has either a single hole
(FIGURE 4A) or multiple holes (FIGURE 4B) within its sidewall.
[0017] FIGURES 5A - 5C show cutaway top view schematics of
illustrative variable flow resistance systems having multiple chambers coupled in
series via a sidewall fluid outlet.
[0018] FIGURES 6A and 6B show side view schematics of a variable
flow resistance system having a chamber with multiple fluid outlets.
[0019] FIGURE 6C shows a cutaway top view schematic of a variable
flow resistance system in which the chamber of FIGURE 6A has been used to
form a branched arrangement of multiple chambers coupled in series.
[0020] FIGURES 7A and 7B show side view schematics of an illustrative
variable flow resistance system in which rotational motion of the fluid occurs at
least partially in parallel to the direction of the fluid flow.
[0021] FIGURE 8A shows a cutaway top view schematic of a variable
flow resistance system having a chamber with both a main flow pathway and a
branch flow pathway within the fluid inlet. FIGURES 8B and 8C show cutaway
top view schematics of a variable flow resistance system in which multiple
chambers having a fluid inlet with a main flow pathway and a branch flow
pathway are series coupled together.
[0022] FIGURE 9 shows a side view s c
resistance system having multiple fluid inlets and fluid outlets interconnecting
chambers of the system.
DETAILED DESCRIPTION
[0023] The present invention generally relates to systems and methods
for regulating fluid flow, particularly within a subterranean formation, and, more
specifically, to rotational motion-inducing variable flow resistance systems
having a sidewall fluid outlet that allows the variable flow resistance systems to
be connected in series fluid communication with one another.
[0024] As discussed above, variable flow resistance systems that induce
rotational motion within a fluid typically can incorporate a fluid exit hole at the
bottom of a chamber, where the location of the exit hole both facilitates vortex
like rotational motion and gravity-assisted draining of the fluid. However, this
location of the exit hole can make series connections between chambers
problematic if a greater degree of fluid flow regulation is needed than can be
provided by a single chamber.
[0025] The embodiments presented herein can address the foregoing
shortcomings in the art. I n particular, the present disclosure describes variable
flow resistance systems that have chambers without a fluid exit hole extending
through the bottom of the chamber. According to the present embodiments, the
chambers instead have a fluid outlet located in a sidewall of the chamber. The
primary advantage of such chambers is that they can be efficiently coupled
together in series in a variable flow resistance system (e.g., in a substantially
horizontal arrangement) without having to conduct excessive vertical movement
of the fluid during transport between adjacent chambers. The substantially
horizontal arrangement offered by the present chambers can also be particularly
efficient in terms of space utilization, such that they can be readily used in
confined regions, such as within a wellbore penetrating a subterranean
formation. Furthermore, the opportunity to connect multiple chambers in series
in a variable flow resistance system can achieve greater fluid flow regulation
than is attainable using a single chamber alone.
[0026] The variable flow resistance systems described herein also offer
advantages in terms of their manufacturing ease. In general, it is believed that
the chambers described herein induce a lower rotational velocity (e.g., less
— Q com para ble chambers having a fluid outlet
exiting through the bottom of the chamber. Altho
rotational motion in a fluid would appear to present an operational disadvantage,
the opportunity to couple multiple chambers in series can overcome the lower
fluid flow restriction provided by a single chamber of the present embodiments.
From a manufacturing standpoint, however, the lower rotational velocities of the
present chambers can result in lesser mechanical stress on the chamber,
thereby allowing variable flow resistance systems to be constructed using
materials having lower mechanical strength. For example, in some
embodiments, the chambers described herein can be constructed through
casting or molding of polymers, polymer composites, ceramics or metals.
Materials having lower mechanical strength can oftentimes be considerably
reduced in cost relative to higher performance materials needed to fabricate
variable flow resistance systems having higher rotational velocities. The
opportunity to use lower cost materials in variable flow resistance systems can
ultimately lead to lower production costs.
[0027] In some embodiments, variable flow resistance systems
described herein can comprise a chamber configured to induce rotational motion
of a fluid flowing therethrough, a fluid inlet coupled to the chamber; and a fluid
outlet coupled to the chamber that allows the fluid to exit through at least a
sidewall of the chamber.
[0028] In some embodiments, multiple chambers can be connected in
series with one another in a variable flow resistance system. I n some
embodiments, variable flow resistance systems described herein can comprise a
plurality of chambers that are connected in series fluid communication with one
another, where each chamber has a fluid inlet and a fluid outlet coupled thereto,
and at least some of the chambers are configured to induce rotational motion of
a fluid flowing therethrough, and the fluid outlets of at least some of the
chambers are configured to allow the fluid to exit through at least a sidewall of
the chamber.
[0029] When multiple chambers are connected in series in a variable
flow resistance system, the chambers can all be the same in some
embodiments, or at least some of the chambers can be different in other
embodiments. I n some embodiments, all of the chambers can have a fluid
outlet that allows a fluid to exit through a sidewall of the chamber. I n other
ing a fluid outlet that allows a fluid to exit through a
sidewall of the chamber can be used in combinatio
fluid outlet exiting through the bottom of the chamber. The choice of a
particular combination of chambers may be dictated by operational needs that
will be evident to one having ordinary skill in the art.
[0030] As used herein, the term "chamber" refers to an enclosed space
having at least one inlet and at least one outlet. As used herein, use of the term
"chamber" makes no implication regarding the shape and/or dimensions of the
chamber unless otherwise specified.
[0031] As used herein, the term "channel" refers to an elongated
passage through which fluids can flow that is open to at least some degree along
its length. I n various embodiments, the closed portion of the channel can be
hemispherical or semi-hemispherical (i.e., tube-like, having only one distinct
surface) or trough-shaped (i.e., having two or more distinct surfaces).
Furthermore, the channel can have shape or dimensional parameters that are
variable along its length.
[0032] As used herein, the term "degree of curvature" refers to at least
some deviation from planarity, particularly in regard to the shape of a surface.
Unless otherwise specified herein, use of the term "degree of curvature" should
not be construed to represent any particular amount or shape of curvature.
[0033] As used herein, the term "sidewall" refers to any surface of
chamber extending between the chamber's top exterior surface and the
chamber's bottom exterior surface. As used herein, the term "exterior" refers to
the outside surface of a chamber that is not in contact with a fluid passing
therethrough.
[0034] As used herein, the term "rotational motion" refers to motion
that occurs around an axis.
[0035] In various embodiments, the variable flow resistance systems of
the present disclosure can be used in a wellbore penetrating a subterranean
formation. FIGURE 2 shows a partial cross-sectional schematic of wellbore in
which the variable flow resistance systems of the present disclosure can be used.
As shown in FIGURE 2, well 10 contains wellbore 12 having generally vertical
uncased section 14, extending from cased section 16, and generally horizontal
uncased section 18 extending through subterranean formation 20. Wellbore
pipe 22 extends through wellbore 12, where wellbore pipe 22 can be any fluid
_,, transported to and from wellbore 12. In some
embodiments, wellbore pipe 22 can be a tubular
tubing string.
[0036] Continuing with FIGURE 2, multiple well screens 24, each in
fluid flow communication with variable flow resistance system 25, can be
connected to wellbore pipe 22. Packers 26 can seal annulus 28 defined by
wellbore pipe 22 and the interior surface of horizontal uncased section 18.
Packers 26 can provide zonal isolation of various subterranean zones penetrated
by wellbore pipe 22, thereby allowing fluids 30 to be produced from or
introduced into some or all of the zones of subterranean formation 20. Well
screens 24 can filter fluids 30 as they move toward the interior of wellbore pipe
22. Each variable flow resistance system 25 can regulate access of fluids 30 to
the interior of wellbore pipe 22 and/or restrict the flow of certain types of fluids
30 based upon certain characteristics or physical properties thereof.
[0037] It is to be noted that the variable flow resistance systems
described herein are not limited to the implementation displayed in FIGURE 2,
which has been presented merely for purposes of illustration and not limitation.
For example, the type of wellbore in which the present variable flow resistance
systems can be used is not particularly limited, and it is not necessary that
wellbore 12 contain either vertical uncased section 14 or horizontal uncased
section 18. Furthermore, any section of wellbore 12 can be cased or uncased,
and wellbore pipe 22 can be placed in any cased or uncased wellbore section.
[0038] Furthermore, it is not necessarily the case that fluids 30 are
solely produced from subterranean formation 20, since fluids can be injected
into subterranean formation 20 and produced therefrom in some embodiments.
In addition, the various elements coupled to wellbore pipe 22 that are presented
in FIGURE 2 are all optional, and each may not necessarily be used in each
subterranean zone, if at all. In some embodiments, however, the various
elements coupled to wellbore pipe 22 can be duplicated in each subterranean
zone. Still further, zonal isolation using packers 26 need not necessarily be
performed, or other types of zonal isolation techniques familiar to one having
ordinary skill in the art can be used.
[0039] In various non-limiting embodiments, the present variable flow
resistance systems can be used to prevent water coning or gas coning from
subterranean formation 20. In some embodiments, the present variable flow
usec j Q qu a |jz pressure and balance production
between heel 13 and toe 11 of wellbore 12. I n ot
variable flow resistance systems can be used to minimize the production of
undesired fluids and to maximize the production of desired fluids. It is also to be
recognized that the wellbore flow control devices can be used for injection
operations as well to accomplish similar advantages to those noted above.
[0040] Whether a fluid is a desired fluid or an undesired fluid will
usually be determined by the nature of the subterranean operation being
conducted. For example, if the goal of a subterranean operation is to produce oil
but not natural gas or water, the oil can be considered a desired fluid and the
natural gas and water can be considered undesired fluids. In other cases,
natural gas can be a desired fluid, and water can be an undesired fluid. It
should be noted that at downhole temperatures and pressures, natural gas can
be at least partially liquefied, and in the disclosure presented herein, the term
"natural gas" or more simply "gas" will refer to a hydrocarbon gas (e.g.,
methane) that is ordinarily in the gas phase at atmospheric pressure and room
temperature.
[0041] In general, the variable flow resistance systems described herein
can be used in any subterranean operation in which there is a need to regulate
the flow of fluids to or from the interior of a wellbore pipe. Reasons why one of
ordinary skill in the art might wish to regulate the flow of fluids can include, for
example, to prevent or minimize water and/or gas coning, to prevent or
minimize water and/or gas production, to prevent or minimize sand production,
to maximize oil production, to better balance production from various
subterranean zones, to better equalize pressure among various subterranean
zones, and/or the like.
[0042] In particular, the variable flow resistance systems described
herein can be used during production or injection operations within a
subterranean formation in some embodiments. I n some embodiments, methods
for using the variable flow resistance systems of the present disclosure can
comprise: installing a wellbore pipe in an uncompleted wellbore, wherein the
wellbore pipe comprises at least one variable flow resistance system that is in
fluid communication with the interior of the wellbore pipe. In such
embodiments, each variable flow resistance system can comprise a plurality of
chambers that are connected in series fluid communication with one another,
jn |e anc j a out |e coupled thereto, and at
least some of the chambers are configured t o indue
flowing therethrough and the fluid outlets of at least some of the chambers are
configured to allow the fluid to exit through at least a sidewall of the chamber.
[0043] In some embodiments, the methods can further comprise
allowing a formation fluid to flow through at least some of the variable flow
resistance systems and into the interior of the wellbore pipe. In some
embodiments, the methods can further comprise producing the formation fluid
from the wellbore pipe.
[0044] In some embodiments, the present variable flow resistance
systems can be used in injection operations. For example, the variable flow
resistance systems can be used to control the introduction of various types of
treatment fluids into a subterranean formation. In injection operations, fluids
that can be injected can include, for example, steam, liquefied gases and water.
The variable flow resistance systems can be used to compensate for heel-to-toe
pressure variations or permeability variations within the subterranean formation.
[0045] In some embodiments, the wellbore can comprise a horizontal
wellbore. In other embodiments, the wellbore can comprise a vertical wellbore.
In some embodiments, the wellbore can comprise a plurality of intervals, where
there is at least one variable flow resistance system located within each interval.
[0046] The present variable flow resistance systems can comprise at
least one chamber that has a fluid outlet coupled to a sidewall of the chamber.
Otherwise, the design of the variable flow resistance systems and their
chambers is not particularly limited. Some illustrative variable flow resistance
systems meeting the above requirement are described in more detail
hereinbelow with reference to the drawings. It is to be recognized that the
drawings presenting variable flow resistance systems with a sidewall fluid outlet
coupled to a chamber therein are for purposes of illustration and not limitation.
Other implementations, orientations, arrangements and combinations of the
features described hereinbelow and presented in the drawings are possible, and
given the benefit of the present disclosure, it will be within the capabilities of one
having ordinary skill in the art to combine these features.
[0047] Commonly owned United States Patent Application 12/869,836,
filed August 27, 2010, which is incorporated herein by reference in its entirety,
describes several examples of chambers that are configured to induce rotational
'-'- e hrough. The chambers described therein can be
adapted to be compatible with those of the presi
through introduction of a sidewall fluid outlet. Specifically, in some
embodiments, the chambers of the present disclosure can contain various flowinducing
structures that induce rotational motion to a fluid flowing therethrough.
In some embodiments, the flow-inducing structures can be formed as vanes or
recesses on or within the sidewall of the chamber. Any number of flow-inducing
structures can be used within the chambers to impart a desired degree of flow
resistance to a fluid passing therethrough.
[0048] Furthermore, in some embodiments, the design of the chambers
can be such that only fluids having certain physical properties can undergo a
desired degree of rotational motion within the chamber. That is, in some
embodiments, the design of the chambers can be configured to take advantage
of a fluid's physical properties such that at least one physical property dictates
the fluid's rate of passage through the chamber. Specifically, fluids having
certain physical properties (e.g., viscosity, velocity and/or density) can be
induced to undergo greater rotational motion when passing through the
chamber, thereby increasing their transit time relative to fluids lacking that
physical property. For example, in some embodiments, the chamber can be
configured to induce increasing rotational motion of a fluid with decreasing fluid
viscosity. Consequently, in such embodiments, a fluid having a greater viscosity
(e.g., oil) can undergo less rotational motion when passing through the chamber
than does a fluid having a lower viscosity (e.g., gas or water), and the high
viscosity fluid can have its transit time through a flow pathway affected to a
much lesser degree than does the low viscosity fluid.
[0049] Various types of sidewall fluid outlets are compatible with the
variable flow resistance systems described herein. In some embodiments, the
fluid outlet can comprise a channel within the chamber that extends from the top
or bottom interior surface of the chamber and through at least a sidewall of the
chamber. That is, the channel can be defined within the top or bottom interior
surface of the chamber, but the channel extends through the sidewall of the
chamber, not the top or bottom of the chamber. In some embodiments, the
fluid outlet can comprise a cone-shaped fluid outlet that extends through at least
a sidewall of the chamber. In some embodiments, the fluid outlet can comprise
at least one hole within the sidewall of the chamber. I n still other embodiments,
a |east one g o o e or slit within the sidewall of the
chamber. Other types of fluid outlets can in
pathways, helical pathways, pathways with directional changes, and segmented
pathways with diameter variations. Combinations of different fluid outlet types
are also possible.
[0050] FIGURE 3A shows a side view schematic of a variable flow
resistance system having a single chamber with a channel extending from the
bottom interior surface of the chamber though a sidewall of the chamber.
FIGURE 3B shows a cutaway top view schematic of a variable flow resistance
system having a single chamber with a channel extending from the bottom
interior surface of the chamber though a sidewall of the chamber. As shown in
FIGURES 3A and 3B, chamber 50 having sidewall 51, top interior surface 52
and bottom interior surface 53 has fluid inlet 54 and fluid outlet 55 coupled
thereto. Chamber 50 has channel 57 defined in bottom interior surface 53 that
establishes a fluid flow pathway extending through sidewall 51 to fluid outlet 55.
According to the present embodiments, channel 57 and fluid outlet 55 do not
extend through the bottom exterior surface of chamber 50.
[0051] FIGURES 3C and 3D show cutaway top view schematics of a
variable flow resistance system having multiple chambers coupled to one
another in series. In FIGURE 3C, fluid inlet 54 and fluid outlet 55 are configured
such that multiple chambers 50 are series connected in a substantially linear
fashion. In FIGURE 3D, fluid inlet 54 and fluid outlet 55 are configured such
that the multiple chambers 50 are connected in a non-linear fashion. According
to the present embodiments, fluid outlet 55 of one chamber can couple to fluid
inlet 54 of a subsequent chamber to establish the series connection
therebetween. Any combination of linear and non-linear arrangements of
chambers 50 can be used within the spirit and scope of the present disclosure.
Furthermore, fluid outlet 55 is not limited to being coupled to channel 57, as
drawn in FIGURES 3A - 3D. Other routes for a fluid's exit from a chamber via its
sidewall are described in more detail hereinbelow and can be used in variable
flow resistance system comparable to those presented in FIGURES 3A - 3D.
[0052] In some alternative embodiments, channel 57 of FIGURES 3A -
3D can be replaced with a cone-shaped fluid exit that extends through a sidewall
of chamber 50. FIGURE 3E shows a side view schematic of a variable flow
resistance system having a single chamber 50 with a cone-shaped fluid exit 58
extending from the bottom interior surface of the cthe chamber.
[0053] FIGURES 4A and 4B show side view schematics of a variable
flow resistance system having a single chamber that has either a single hole
(FIGURE 4A) or multiple holes (FIGURE 4B) within its sidewalk As shown in
FIGURES 4A and 4B, chamber 60 has fluid inlet 61 and fluid outlet 62 coupled
thereto. A fluid can exit chamber 60 through sidewall 63 via hole(s) 65 and
travel through fluid outlet 62. As shown in FIGURE 4B, fluid passing through
each hole 65 can be rejoined into a single-stream fluid output. In alternative
embodiments, fluid passing through each hole 65 can remain as a separated
fluid output stream (not shown), each of which can then separately enter a
subsequent chamber. Series coupling of the chambers to one another can be
accomplished in a manner similar to that shown in FIGURES 3C and 3D above,
where the chamber arrangement can again be either substantially linear or nonlinear.
Furthermore, it is to be recognized that hole(s) 65 can be replaced in
any of the various embodiments with openings such as slits or grooves to
achieve a like result.
[0054] It is to be recognized that whether a substantially linear or non
linear arrangement of chambers is chosen for a multi-chamber variable flow
resistance system will be a matter of operational needs, and one of ordinary skill
in the art will be able to implement a preferred orientation of chambers for a
particular application. Furthermore, it is to be recognized that the depiction of
certain numbers of chambers in the drawings should not be construed as
limiting. According to the present embodiments, any number of chambers can
be series coupled in a multi-chamber variable flow resistance system, including,
for example, 2 chambers to about 20 chambers in some embodiments, or 2
chambers t o about 10 chambers in other embodiments, or 2 chambers to about
5 chambers in still other embodiments. Of course, the chambers can be used
singularly in a variable flow resistance system, if desired.
[0055] In addition to the illustrative arrangements of multiple chambers
that are depicted in FIGURES 3C and 3D, other chamber arrangements are also
possible when a fluid outlet extends through the sidewall of the chamber.
FIGURES 5A - 5C show cutaway top view schematics of illustrative variable flow
resistance systems having multiple chambers 70 coupled in series via sidewall
i . . : j _ these alternative chamber arrangements allow a
particularly efficient utilization of space to be realiz
for example). Again, it should be emphasized that the chamber arrangements
presented in FIGURES 5A - 5C are for purposes of illustration and not limitation,
and any series-connected arrangement of multiple chambers in a variable flow
resistance system can be used within the spirit and scope of the present
disclosure.
[0056] As illustrated in FIGURES 5A - 5C, the shape of the chambers in
the present variable flow resistance systems is not particularly limited.
However, it is to be understood the chambers of the present embodiments are
not limited to the shapes set forth in those or any other drawing unless
otherwise expressly set forth herein. In some embodiments, at least a portion
of the sidewall of a given chamber can have at least some degree of curvature.
In some embodiments, the degree of curvature can be substantially uniform
about the interior of the chamber. That is, the chamber can be approximately
circular in such embodiments. In other embodiments, the degree of curvature
can vary about the interior of the chamber. For example, the chamber can be
approximately elliptical in some embodiments. In embodiments in which the
degree of curvature can vary, considerably more complex shapes of the chamber
can become possible (for example, see FIGURE 5B). In still other embodiments,
a chamber having a portion of its sidewalls with a degree of curvature and a
portion of its sidewalls substantially planar can also be used, if desired.
[0057] Although FIGURES 3A - 3E, 4A - 4B and 5A - 5C have shown
some particular orientations of the fluid inlet and the fluid outlet relative to one
another, the spatial arrangement of these elements should not be considered to
be particularly limited in any regard. In some embodiments, the location of the
fluid inlet can be such that rotational motion is induced in the fluid as it enters
the chamber. For example, the chamber and fluid inlet can be configured such
that fluid entering the chamber is introduced along a curved sidewall of the
chamber, which can set the fluid into rotational motion within the chamber.
Furthermore, there are no limitations regarding the separation of the fluid inlet
and the fluid outlet from one another along the sidewalls of the chamber.
Generally, at least some degree of separation can be maintained between the
fluid inlet and the fluid outlet so that an undesired fluid does not enter the fluid
outlet without first undergoing rotational motion, but this is not necessarily the
- __„ .. _,_ and the |ujd out |e t ca n e |ocate d at any height
relative to one another. In some embodiments, t h
fluid outlet. In other embodiments, the fluid inlet can be above the fluid outlet.
In still other embodiments, the fluid inlet and the fluid outlet can be at
approximately the same height above the bottom of the chamber.
[0058] In some embodiments, there can be a single fluid inlet coupled
to the chamber(s) of the variable flow resistance systems. In other
embodiments, there can be more than one fluid inlet coupled to the chamber(s)
of the variable flow resistance systems.
[0059] In some embodiments, there can be a single fluid outlet coupled
to the chamber(s) of the variable flow resistance systems. In other
embodiments, there can be more than one fluid outlet coupled to the
chamber(s) of the variable flow resistance systems. That is, in some
embodiments, a fluid can exit the chamber(s) at more than one point. In some
embodiments, a channel extending from the top or bottom interior surface of the
chamber can extend through a sidewall of the chamber(s) at more than one
point. In some or other embodiments, there can be multiple holes or like exit
ports within the sidewall of the chamber(s). The presence of multiple fluid
outlets within the chamber(s) can allow a variable flow resistance system having
a "branched" arrangement of chambers to be constructed.
[0060] FIGURES 6A and 6B show side view schematics of a variable
flow resistance system having a chamber with multiple fluid outlets. FIGURE 6A
shows chamber 80 in which channel 81 splits into multiple fluid outlets 82
extending through sidewall 83 of the chamber. FIGURE 6B shows chamber 85
in which there are multiple holes 86 extending through sidewall 87 of the
chamber. FIGURE 6C shows a cutaway top view schematic of a variable flow
resistance system in which the chamber of FIGURE 6A has been used to form a
branched arrangement of multiple chambers coupled in series. Although FIGURE
6C has shown only a single branch initiated from chamber 80, it is t o be
recognized that further branching can take place if desired by replacing any of
chamber(s) 50 with chamber 80 or a like chamber having multiple fluid outlets.
Further, it should be recognized that any number of fluid outlets can extend from
a sidewall of chamber 80, and the depiction of three fluid outlets in FIGURES 6A
- 6C should be considered to be for purposes of illustration and not limitation.
[0061] The rotational motion induced within a fluid passing through the
- jSC|0Sure can b jn a n y direction relative to the
forward motion of the fluid. In some embodiments,
substantially normal to the direction of the fluid flow. That is, in the chamber of
FIGURE 3A or another like chamber described herein, the rotational motion can
take place as the fluid passes along the sidewalls of the chamber while it passes
to the fluid outlet. In some embodiments, the chamber can be configured such
that the rotation motion occurs in the same direction as the fluid flow, that is,
substantially parallel to the fluid flow. In some embodiments, the chamber can
be configured such that rotational motion of the fluid occurs at least partially in
parallel to the direction of the fluid flow. In some embodiments, the rotational
motion can occur with a component that is substantially normal and a
component that is substantially parallel t o the fluid flow.
[0062] FIGURES 7A and 7B show side view schematics of an illustrative
variable flow resistance system in which rotational motion of the fluid occurs at
least partially in parallel to the direction of the fluid flow. As shown in FIGURES
7A and 7B, a fluid enters chamber 100 through fluid inlet 101 and exits through
fluid outlet 102. In region 103, the fluid can either rotate substantially normal
to the forward direction of fluid motion or not rotate to a significant degree.
Once the fluid progresses forward and encounters vane 105, rotational motion is
induced in the fluid in region 104, where the rotational motion is at least
partially in parallel to the forward direction of the fluid motion.
[0063] In some embodiments, the fluid inlets coupled to the chambers
of the present disclosure can comprise both a main flow pathway and a branch
flow pathway. In some embodiments, the branch flow pathway can be
configured such that fluid entering the branch flow pathway does not undergo
rotational motion or undergoes less rotational motion than fluid entering the
main flow pathway. FIGURE 8A shows a cutaway top view schematic of a
variable flow resistance system having a chamber with both a main flow pathway
and a branch flow pathway within the fluid inlet. As shown in FIGURE 8A,
chamber 90 includes fluid inlet 91 and channel 92 extending through sidewall
93 into fluid outlet 94. Fluid inlet 91 further comprises main flow pathway 91'
and branch flow pathway 91". As one of ordinary skill in the art will recognize,
low viscosity fluids, such as water or gas, will tend to enter main flow pathway
91', since they have a higher ratio of momentum to viscosity than more viscous
fluids (e.g., oil), such that they tend not to make the turn into branch flow
« — ..: fluids, in contrast, by virtue of their lower ratio of
momentum to viscosity can more readily make t
flow pathway 91". Outlet 95 of branch flow pathway 91" can be located within
chamber 90 such that high viscosity fluid passing therethrough can undergo less
rotational motion via bypassing the portion of chamber 90 that induces
rotational motion in the fluid and/or by being located in or near channel 92,
which leads to fluid outlet 94. In some embodiments, outlet 95 can completely
bypass chamber 90 such that a fluid passing therethrough is discharged directly
into outlet 94.
[0064] Similar to the embodiments described above, chambers having
fluid inlets with both main and branch flow pathways can likewise be series
coupled to one another. FIGURE 8B shows a cutaway top view schematic of a
variable flow resistance system in which multiple chambers having a fluid inlet
with a main flow pathway and a branch flow pathway are series coupled
together. As drawn in FIGURE 8B, outlet 95 of branch flow pathway 91"
discharged near channel 92. FIGURE 8C shows an alternative embodiment to
that presented in FIGURE 8B, in which fluid outlet 95 of branch flow pathway
91" is discharged directly into fluid outlet 94, thereby preventing a fluid passing
therethrough from undergoing rotational motion. In FIGURE 8C, branch flow
pathway 91" is structurally connected to fluid outlet 95, thereby allowing
chamber 90 to be bypassed altogether. In both cases, main flow pathway 91'
discharges into chamber 90 and fluid therein can undergo rotational motion.
[0065] Another embodiment of a variable flow resistance system having
a branch flow pathway is shown in FIGURE 9 . FIGURE 9 shows a side view
schematic of a variable flow resistance system 110 having multiple fluid inlets
111 and fluid outlets 112 interconnecting chambers 113, 114, 115 and 116.
Lower viscosity fluids (solid line) such as, for example, oil and gas can enter
main flow pathway 118 and undergo rotational motion within chamber 114.
The lower viscosity fluids can subsequently bypass branch flow pathways in
chambers 114 and 115 and undergo additional rotational motion in these
chambers. In contrast, a higher viscosity fluid (dashed line) such as oil, for
example, can enter branch flow pathway 118'. As the higher viscosity fluid
enters chamber 114, it has less opportunity to undergo rotational motion and
can subsequently enter branch flow pathways in chambers 114 and 115.
Accordingly, the transit rate of the higher viscosity fluid relative to the lower
[0066] Therefore, the present invention i :
ends and advantages mentioned as well as those that are inherent therein. The
particular embodiments disclosed above are illustrative only, as the present
invention may be modified and practiced in different but equivalent manners
apparent t o those skilled in the art having the benefit of the teachings herein.
Furthermore, no limitations are intended to the details of construction or design
herein shown, other than as described in the claims below. It is therefore
evident that the particular illustrative embodiments disclosed above may be
altered, combined, or modified and all such variations are considered within the
scope and spirit of the present invention. The invention illustratively disclosed
herein suitably may be practiced in the absence of any element that is not
specifically disclosed herein and/or any optional element disclosed herein. While
compositions and methods are described in terms of "comprising," "containing,"
or "including" various components or steps, the compositions and methods can
also "consist essentially of or "consist of the various components and steps. All
numbers and ranges disclosed above may vary by some amount. Whenever a
numerical range with a lower limit and an upper limit is disclosed, any number
and any included range falling within the range is specifically disclosed. In
particular, every range of values (of the form, "from about a to about b," or,
equivalently, "from approximately a to b," or, equivalently, "from approximately
a-b") disclosed herein is to be understood to set forth every number and range
encompassed within the broader range of values. Also, the terms in the claims
have their plain, ordinary meaning unless otherwise explicitly and clearly defined
by the patentee. Moreover, the indefinite articles "a" or "an," as used in the
claims, are defined herein to mean one or more than one of the element that it
introduces. I f there is any conflict in the usages of a word or term in this
specification and one or more patent or other documents that may be
incorporated herein by reference, the definitions that are consistent with this
specification should be adopted.

CLAIMS
The invention claimed is:
1. A variable flow resistance system comprising:
a chamber configured to induce rotational motion of a fluid flowing
therethrough;
a fluid inlet coupled to the chamber; and
a fluid outlet coupled to the chamber that allows the fluid to exit
through at least a sidewall of the chamber.
2 . The variable flow resistance system of claim 1, wherein the fluid outlet
comprises a channel within the chamber that extends from the top or bottom
interior surface of the chamber through at least a sidewall of the chamber.
3. The variable flow resistance system of claim 2, wherein the channel exits
through the sidewall of the chamber at more than one point.
4 . The variable flow resistance system of claim 1, wherein the fluid outlet
comprises at least one hole in the sidewall of the chamber.
5. The variable flow resistance system of claim 1, wherein at least a portion of
the sidewall of the chamber has at least some degree of curvature.
6 . The variable flow resistance system of claim 1, wherein the chamber is
configured such that the rotational motion occurs, at least in part, in the
same direction as the fluid flow.
7 . The variable flow resistance system of claim 1, wherein the fluid inlet
comprises a main flow pathway and a branch flow pathway;
wherein the branch flow pathway is configured such that fluid entering
the branch flow pathway does not undergo rotational motion or undergoes
less rotational motion than fluid entering the main flow pathway.
8 . The variable flow resistance system of claim 7, wherein the branch flow
pathway is structurally connected to the fluid outlet.
9 . The variable flow resistance system of claim 1, wherein the chamber is
configured to induce increasing rotational motion of the fluid with decreasing
fluid viscosity.
10. A variable flow resistance system comprising:
a plurality of chambers that are connected in series fluid
communication with one another, each chamber having a fluid inlet and a
fluid outlet coupled thereto;
wherein at least some of the chambers are configured to induce
rotational motion of a fluid flowing therethrough; and
wherein the fluid outlets of at least some of the chambers are
configured to allow the fluid to exit through at least a sidewall of the
chamber.
11. The variable flow resistance system of claim 10, wherein at least some of the
chambers are configured such that the rotational motion occurs, at least in
part, in the same direction as the fluid flow.
12. The variable flow resistance system of claim 10, wherein at least some of the
chambers are configured to induce increasing rotational motion of the fluid
with decreasing fluid viscosity.
13. The variable flow resistance system of claim 10, wherein at least some of the
chambers have at least some degree of curvature in at least a portion of the
sidewall of the chamber.
14. The variable flow resistance system of claim 10, wherein the fluid outlet of at
least some of the chambers comprises a channel within the chamber that
extends from the top or bottom interior surface of the chamber through at
least a sidewall of the chamber.
15. The variable flow resistance system of claim 10, wherein the fluid outlet of at
least some of the chambers comprises at least one hole in the sidewall of the
chamber.
16. The variable flow resistance system of claim 10, wherein the fluid inlets of at
least some of the chambers comprise a main flow pathway and a branch flow
pathway;
wherein the branch flow pathway is configured such that fluid entering
the branch flow pathway does not undergo rotational motion or undergoes
less rotational motion than fluid entering the main flow pathway.
17. The variable flow resistance system of claim 16, wherein the branch flow
pathway is structurally connected to the fluid outlet in at least some of the
chambers.
18. A method comprising :
installing a wellbore pipe in an uncompleted wellbore;
wherein the wellbore pipe comprises at least one variable flow
resistance system in fluid communication with the interior of the wellbore
pipe, each variable flow resistance system comprising :
a plurality of chambers that are connected in series fluid
communication with one another, each chamber having a fluid inlet and a
fluid outlet coupled thereto;
wherein at least some of the chambers are configured to
induce rotational motion of a fluid flowing therethrough; and
wherein the fluid outlets of at least some of the chambers
are configured to allow the fluid to exit through at least a sidewall of the
chamber.
19. The method of claim 18, further comprising :
allowing a formation fluid to flow through at least some of the variable
flow resistance systems and into the interior of the wellbore pipe; and
producing the formation fluid from the wellbore pipe.
20. The method of claim 18, wherein the uncompleted wellbore comprises a
horizontal wellbore.
21. The method of claim 18, wherein the uncompleted wellbore penetrates a
subterranean formation comprising a plurality of intervals; and
wherein there is at least one variable flow resistance system within
each interval.