U.S. patent application number 13/438872 was filed with the patent office on 2014-09-25 for method and apparatus for controlling fluid flow in an autonomous valve using a sticky switch.
This patent application is currently assigned to HALLIBURTON ENERGY SERVICES, INC.. The applicant listed for this patent is Jason D. Dykstra, Michael L. Fripp. Invention is credited to Jason D. Dykstra, Michael L. Fripp.
Application Number | 20140284062 13/438872 |
Document ID | / |
Family ID | 46965210 |
Filed Date | 2014-09-25 |
United States Patent
Application |
20140284062 |
Kind Code |
A9 |
Fripp; Michael L. ; et
al. |
September 25, 2014 |
METHOD AND APPARATUS FOR CONTROLLING FLUID FLOW IN AN AUTONOMOUS
VALVE USING A STICKY SWITCH
Abstract
Apparatus and methods are described for autonomously controlling
fluid flow in a tubular in a wellbore. A fluid is flowed through an
inlet passageway into a biasing mechanism. A fluid flow
distribution is established across the biasing mechanism. The fluid
flow distribution is altered in response to a change in the fluid
characteristic over time. In response, fluid flow through a
downstream sticky switch assembly is altered, thereby altering
fluid flow patterns in a downstream vortex assembly. The method
"selects" based on a fluid characteristic, such as viscosity,
density, velocity, flow rate, etc. The biasing mechanism can take
various forms such as a widening passageway, contour elements along
the biasing mechanism, or a curved section of the biasing mechanism
passageway. The biasing mechanism can include hollows formed in the
passageway wall, obstructions extending from the passageway wall,
fluid diodes, Tesla fluid diodes, a chicane, or abrupt changes in
passageway cross-section.
Inventors: |
Fripp; Michael L.;
(Carrollton, TX) ; Dykstra; Jason D.; (Carrollton,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fripp; Michael L.
Dykstra; Jason D. |
Carrollton
Carrollton |
TX
TX |
US
US |
|
|
Assignee: |
HALLIBURTON ENERGY SERVICES,
INC.
Houston
TX
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20120255740 A1 |
|
|
US 20140048280 A9 |
February 20, 2014 |
|
|
Family ID: |
46965210 |
Appl. No.: |
13/438872 |
Filed: |
April 4, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12700685 |
Feb 4, 2010 |
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13438872 |
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12542695 |
Aug 18, 2009 |
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12700685 |
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12791993 |
Jun 2, 2010 |
8235128 |
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12542695 |
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61473669 |
Apr 8, 2011 |
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Current U.S.
Class: |
166/373 |
Current CPC
Class: |
E21B 43/12 20130101;
E21B 43/14 20130101 |
Class at
Publication: |
166/373 |
International
Class: |
E21B 34/08 20060101
E21B034/08 |
Claims
1. A method for controlling flow of fluid in a wellbore extending
through a subterranean formation, the fluid having a characteristic
which changes over time, the fluid flowing through an inlet
passageway, a flow biasing mechanism, and a variable flow
resistance assembly, the method comprising the following steps:
flowing fluid through the inlet passageway; establishing a first
fluid flow distribution across an outlet of the flow biasing
mechanism; then altering the first fluid flow distribution to a
second flow distribution across the outlet of the flow biasing
mechanism in response to a change in the fluid characteristic; and
changing the fluid flow resistance of the variable flow resistance
assembly in response to the altering of the distribution of flow
from the outlet of the flow biasing mechanism.
2. A method as in claim 1, further comprising the step of flowing
the fluid to the surface or into the formation.
3. A method as in claim 1, further comprising the steps of
establishing a first flow pattern in the variable flow resistance
assembly, and then changing the flow in the variable flow
resistance assembly to a second flow pattern in response to the
altering of the fluid flow through the outlet of the flow biasing
mechanism.
4. A method as in claim 1, wherein the characteristic of the fluid
is one of fluid velocity, density, flow rate, and velocity.
5. A method as in claim 1, wherein the biasing mechanism is a
widening passageway narrower at the upstream end and wider at the
downstream end.
6. A method as in claim 5, wherein the downstream end of the
biasing mechanism defines two sides which connect to corresponding
first and second sides of a fluidic switch assembly, corresponding
first and second departure angles defined at the connections, and;
wherein the first departure angle is shallower than the second
departure angle.
7. A method as in claim 1, wherein the first fluid flow
distribution is substantially symmetric.
8. A method as in claim 1, wherein the biasing mechanism includes
at least one contour element along at least one side of the biasing
mechanism.
9. A method as in claim 8, wherein each contour element comprises a
laterally extending hollow.
10. A method as in claim 9, wherein each contour element includes a
substantially cylindrical section.
11. A method as in claim 1, wherein the biasing mechanism includes
a first section having a first cross-sectional size and an
adjoining second section having a second cross-sectional size,
different from the first cross-sectional size.
12. A method as in claim 1, wherein the biasing mechanism includes
one or more diodes formed along the biasing mechanism wall.
13. A method as in claim 1, wherein the biasing mechanism includes
a chicane defined in the biasing mechanism.
14. A method as in claim 13, wherein the chicane includes a
plurality of flow obstructions on a first and second side of the
biasing mechanism.
15. A method as in claim 1, further comprising the step of flowing
fluid through a curved section of a biasing mechanism
passageway.
16. A method as in claim 1, wherein the variable flow resistance
assembly includes an autonomous valve assembly.
17. A method as in claim 1, further comprising the step of flowing
fluid through a fluidic switch between the biasing mechanism and
the variable flow resistance assembly.
18. A method as in claim 17, the fluidic switch defining at least
one flow passageway having an inlet coincident with the outlet of
the inlet passageway.
19. A method as in claim 2, further comprising the step of
increasing the fluid flow resistance of an undesirable fluid.
20. A method as in claim 16, wherein the autonomous valve assembly
further includes a vortex assembly.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. provisional
application Ser. No. 61/473,669, filed Apr. 8, 2011, which is
incorporated herein by reference for all purposes.
FIELD OF INVENTION
[0002] The invention relates generally to methods and apparatus of
control of an autonomous fluid valve using a "sticky switch" or
biasing mechanism to control fluid flow, and more specifically to
use of such mechanisms to control fluid flow between a hydrocarbon
bearing subterranean formation and a tool string in a wellbore.
BACKGROUND OF INVENTION
[0003] During the completion of a well that traverses a hydrocarbon
bearing subterranean formation, production tubing and various
equipment are installed in the well to enable safe and efficient
production of the fluids. For example, to prevent the production of
particulate material from an unconsolidated or loosely consolidated
subterranean formation, certain completions include one or more
sand control screens positioned proximate the desired production
intervals. In other completions, to control the flow rate of
production fluids into the production tubing, it is common practice
to install one or more inflow control devices with the completion
string.
[0004] Production from any given production tubing section can
often have multiple fluid components, such as natural gas, oil and
water, with the production fluid changing in proportional
composition over time. Thereby, as the proportion of fluid
components changes, the fluid flow characteristics will likewise
change. For example, when the production fluid has a
proportionately higher amount of natural gas, the viscosity of the
fluid will be lower and density of the fluid will be lower than
when the fluid has a proportionately higher amount of oil. It is
often desirable to reduce or prevent the production of one
constituent in favor of another. For example, in an oil-producing
well, it may be desired to reduce or eliminate natural gas
production and to maximize oil production. While various downhole
tools have been utilized for controlling the flow of fluids based
on their desirability, a need has arisen for a flow control system
for controlling the inflow of fluids that is reliable in a variety
of flow conditions. Further, a need has arisen for a flow control
system that operates autonomously, that is, in response to changing
conditions downhole and without requiring signals from the surface
by the operator. Further, a need has arisen for a flow control
system without moving mechanical parts which are subject to
breakdown in adverse well conditions including from the erosive or
clogging effects of sand in the fluid. Similar issues arise with
regard to injection situations, with flow of fluids going into
instead of out of the formation.
SUMMARY OF THE INVENTION
[0005] An apparatus and method are described for autonomously
controlling flow of fluid in a tubular positioned in a wellbore
extending through a hydrocarbon-bearing subterranean formation. In
a method, a fluid is through an inlet passageway into a biasing
mechanism. A first fluid flow distribution is established across
the outlet of the flow biasing mechanism. The fluid flow is altered
to a second flow distribution across the outlet of the flow biasing
mechanism in response to a change in the fluid characteristic over
time. In response, the fluid flow through a downstream sticky
switch assembly is altered, thereby altering fluid flow patterns in
a downstream vortex assembly. The fluid flow through the vortex
assembly "selects" for fluid of a preferred characteristic, such as
more or less viscous, dense, of greater or lesser velocity, etc.,
by inducing more or less spiraled flow through the vortex.
[0006] The biasing mechanism can take various embodiments. The
biasing mechanism can include a widening of the fluid passageway,
preferably from narrower at the upstream end and to wider at the
downstream end. Alternately, the biasing mechanism can include at
least one contour element along at least one side of the biasing
mechanism. The contour elements can be hollows formed in the
passageway wall or obstructions extending from the passageway wall.
The biasing mechanism can include fluid diodes, Tesla fluid diodes,
a chicane, an abrupt change in passageway cross-section, or a
curved section of passageway.
[0007] The downhole tubular can include a plurality of flow control
systems. The flow control systems can be used in production and
injection methods. The flow control systems autonomously select for
fluid of a desired characteristic as that characteristic changes
over time.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] 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:
[0009] FIG. 1 is a schematic illustration of a well system
including a plurality of autonomous flow control systems embodying
principles of the present invention;
[0010] FIG. 2 is a side view in cross-section of a screen system
and an embodiment of a flow control system of the invention;
[0011] FIG. 3 is a schematic representational view of a prior art,
"control jet" type, autonomous flow control system 60;
[0012] FIG. 4A-B are flow charts comparing the prior art,
control-jet type of autonomous valve assembly and the sticky-switch
type of autonomous valve assembly presented herein;
[0013] FIG. 5 is a schematic of a preferred embodiment of a sticky
switch type autonomous valve according to an aspect of the
invention;
[0014] FIGS. 6A-B are graphical representations of a relatively
more viscous fluid flowing through the exemplary assembly;
[0015] FIG. 7A-B are graphical representations of a relatively less
viscous fluid flowing through the exemplary assembly;
[0016] FIG. 8 is a schematic view of an alternate embodiment of the
invention having a biasing mechanism employing wall contour
elements;
[0017] FIG. 9 is a detail schematic view of an alternate embodiment
of the invention having a biasing element including contour
elements and a stepped cross-sectional passageway shape;
[0018] FIG. 10 is a schematic view of an alternate embodiment of
the invention having fluidic diode shaped cut-outs as contour
elements in the biasing mechanism;
[0019] FIG. 11 is a schematic view of an alternate embodiment of
the invention having Tesla diodes along the first side of the fluid
passageway; and
[0020] FIG. 12 is a schematic view of an alternate embodiment of
the invention having a chicane 214, or a section of the biasing
mechanism passageway 141 having a plurality of bends 216 created by
flow obstacles 218 and 220 positioned along the sides of the
passageway. It should be understood by those skilled in the art
that the use of directional terms such as above, below, upper,
lower, upward, downward and the like are used 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. Where this is not the case and a term is
being used to indicate a required orientation, the Specification
will state or make such clear. Uphole and downhole are used to
indicate relative location or direction in relation to the surface,
where upstream indicates relative position or movement towards the
surface along the wellbore and downstream indicates relative
position or movement further away from the surface along the
wellbore, regardless of whether in a horizontal, deviated or
vertical wellbore. The terms upstream and downstream are used to
indicate relative position or movement of fluid in relation to the
direction of fluid flow.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0021] While the making and using of various embodiments of the
present invention are discussed in detail below, a practitioner of
the art will appreciate that the present invention provides
applicable inventive concepts which can be embodied in a variety of
specific contexts. The specific embodiments discussed herein are
illustrative of specific ways to make and use the invention and do
not limit the scope of the present invention.
[0022] FIG. 1 is a schematic illustration of a well system,
indicated generally 10, including a plurality of autonomous flow
control systems embodying principles of the present invention. A
wellbore 12 extends through various earth strata. Wellbore 12 has a
substantially vertical section 14, the upper portion of which has
installed therein a casing string 16. Wellbore 12 also has a
substantially deviated section 18, shown as horizontal, which
extends through a hydrocarbon-bearing subterranean formation 20. As
illustrated, substantially horizontal section 18 of wellbore 12 is
open hole. While shown here in an open hole, horizontal section of
a wellbore, the invention will work in any orientation, and in open
or cased hole. The invention will also work equally well with
injection systems, as will be discussed supra.
[0023] Positioned within wellbore 12 and extending from the surface
is a tubing string 22. Tubing string 22 provides a conduit for
fluids to travel from formation 20 upstream to the surface.
Positioned within tubing string 22 in the various production
intervals adjacent to formation 20 are a plurality of autonomous
flow control systems 25 and a plurality of production tubing
sections 24. At either end of each production tubing section 24 is
a packer 26 that provides a fluid seal between tubing string 22 and
the wall of wellbore 12. The space in-between each pair of adjacent
packers 26 defines a production interval.
[0024] In the illustrated embodiment, each of the production tubing
sections 24 includes sand control capability. Sand control screen
elements or filter media associated with production tubing sections
24 are designed to allow fluids to flow therethrough but prevent
particulate matter of sufficient size from flowing therethrough.
While the invention does not need to have a sand control screen
associated with it, if one is used, then the exact design of the
screen element associated with fluid flow control systems is not
critical to the present invention. There are many designs for sand
control screens that are well known in the industry, and will not
be discussed here in detail. Also, a protective outer shroud having
a plurality of perforations therethrough may be positioned around
the exterior of any such filter medium.
[0025] Through use of the flow control systems 25 of the present
invention in one or more production intervals, some control over
the volume and composition of the produced fluids is enabled. For
example, in an oil production operation if an undesired fluid
component, such as water, steam, carbon dioxide, or natural gas, is
entering one of the production intervals, the flow control system
in that interval will autonomously restrict or resist production of
fluid from that interval.
[0026] The term "natural gas" as used herein means a mixture of
hydrocarbons (and varying quantities of non-hydrocarbons) that
exist in a gaseous phase at room temperature and pressure. The term
does not indicate that the natural gas is in a gaseous phase at the
downhole location of the inventive systems. Indeed, it is to be
understood that the flow control system is for use in locations
where the pressure and temperature are such that natural gas will
be in a mostly liquefied state, though other components may be
present and some components may be in a gaseous state. The
inventive concept will work with liquids or gases or when both are
present.
[0027] The fluid flowing into the production tubing section 24
typically comprises more than one fluid component. Typical
components are natural gas, oil, water, steam or carbon dioxide.
Steam and carbon dioxide are commonly used as injection fluids to
drive the hydrocarbon towards the production tubular, whereas
natural gas, oil and water are typically found in situ in the
formation. The proportion of these components in the fluid flowing
into each production tubing section 24 will vary over time and
based on conditions within the formation and wellbore. Likewise,
the composition of the fluid flowing into the various production
tubing sections throughout the length of the entire production
string can vary significantly from section to section. The flow
control system is designed to reduce or restrict production from
any particular interval when it has a higher proportion of an
undesired component.
[0028] Accordingly, when a production interval corresponding to a
particular one of the flow control systems produces a greater
proportion of an undesired fluid component, the flow control system
in that interval will restrict or resist production flow from that
interval. Thus, the other production intervals which are producing
a greater proportion of desired fluid component, in this case oil,
will contribute more to the production stream entering tubing
string 22. In particular, the flow rate from formation 20 to tubing
string 22 will be less where the fluid must flow through a flow
control system (rather than simply flowing into the tubing string).
Stated another way, the flow control system creates a flow
restriction on the fluid.
[0029] Though FIG. 1 depicts one flow control system in each
production interval, it should be understood that any number of
systems of the present invention can be deployed within a
production interval without departing from the principles of the
present invention. Likewise, the inventive flow control systems do
not have to be associated with every production interval. They may
only be present in some of the production intervals in the wellbore
or may be in the tubing passageway to address multiple production
intervals.
[0030] FIG. 2 is a side view in cross-section of a screen system
28, and an embodiment of a flow control system 25 of the invention.
The production tubular defines an interior screen annulus or
passageway 32. Fluid flows from the formation 20 into the
production tubing section 24 through screen system 28. The
specifics of the screen system are not explained in detail here.
Fluid, after being filtered by the screen system 28, flows into the
interior passageway 32 of the production tubing section 24. As used
here, the interior passageway 32 of the production tubing section
24 can be an annular space, as shown, a central cylindrical space,
or other arrangement.
[0031] A port 42 provides fluid communication from the screen
annulus 32 to a flow control system having a fluid passageway 44, a
switch assembly 46, and an autonomous, variable flow resistance
assembly 50, such as a vortex assembly. If the variable flow
resistance assembly is an exemplary vortex assembly, it includes a
vortex chamber 52 in fluid communication with an outlet passageway
38. The outlet passageway 38 directs fluid into a passageway 36 in
the tubular for production uphole, in a preferred embodiment. The
passageway 36 is defined in this embodiment by the tubular wall
31.
[0032] The methods and apparatus herein are intended to control
fluid flow based on changes in a fluid characteristic over time.
Such characteristics include viscosity, velocity, flow rate, and
density. These characteristics are discussed in more detail in the
references incorporated herein. The term "viscosity" as used herein
means any of the rheological properties including kinematic
viscosity, yield strength, viscoplasticity, surface tension,
wettability, etc. As the proportional amounts of fluid components,
for example, oil and natural gas, in the produced fluid change over
time, the characteristic of the fluid flow also changes. When the
fluid contains a relatively high proportion of natural gas, for
example, the density and viscosity of the fluid will be less than
for oil. The behavior of fluids is dependent on the characteristics
of the fluid flow. Further, certain configurations of passageway
will restrict flow, or provide greater resistance to flow,
depending on the characteristics of the fluid flow.
[0033] FIG. 3 is a schematic representational view of a prior art,
"control jet" type autonomous flow control system 60. The control
jet type system 60 includes a fluid selector assembly 70, a fluidic
switch 90, and a variable flow resistance assembly, here a vortex
assembly 100. The fluid selector assembly 70 has a primary fluid
passageway 72 and a control jet assembly 74. An exemplary
embodiment is shown; prior art systems are fully discussed in the
references incorporated herein. An exemplary system will be
discussed for comparison purposes.
[0034] The fluid selector assembly 70 has a primary fluid
passageway 72 and a control jet assembly 74. The control jet
assembly 74 has a single control jet passageway 76. Other
embodiments may employ additional control jets. The fluid F enters
the fluid selector assembly 70 at the primary passageway 72 and
flows towards the fluidic switch 90. A portion of the fluid flow
splits off from the primary passageway 72 to the control jet
assembly 74. The control jet assembly 74 includes a control jet
passageway 76 having at least one inlet 77 providing fluid
communication to the primary passageway 72, and an outlet 78
providing fluid communication to the fluidic switch assembly 90. A
nozzle 71 can be provided if desired to create a "jet" of fluid
upon exit, but it not required. The outlet 78 is connected to the
fluidic switch assembly 90 and directs fluid (or communicates
hydrostatic pressure) to the fluidic switch assembly. The control
jet outlet 78 and the downstream portion 79 of the control jet
passageway 72 longitudinally overlap the lower portion 92 of the
fluidic switch assembly 90, as shown.
[0035] The exemplary control jet assembly further includes a
plurality of inlets 77, as shown. The inlets preferably include
flow control features 80, such as the chambers 82 shown, for
controlling the volume of fluid F which enters the control jet
assembly from the primary passageway dependent on the
characteristic of the fluid. That is, the fluid selector assembly
70 "selects" for fluid of a preferred characteristic. In the
embodiment shown, where the fluid is of a relatively higher
viscosity, such as oil, the fluid flows through the inlets 77 and
the control passageway 76 relatively freely. The fluid exiting the
downstream portion 79 of the control jet passageway 72 through
nozzle 78, therefore, "pushes" the fluid flowing from the primary
passageway after its entry into the fluidic switch 90 at mouth 94.
The control jet effectively directs the fluid flow towards a
selected side of the switch assembly. In this case, where the
production of oil is desired, the control jet directs the fluid
flow through the switch 90 along the "on" side. That is, fluid is
directed through the switch towards the switch "on" passageway 96
which, in turn, directs the fluid into the vortex assembly to
produce a relatively direct flow toward the vortex outlet 102, as
indicated by the solid arrow.
[0036] A relatively less viscous fluid, such as water or natural
gas, will behave differently. A relatively lower volume of fluid
will enter the control jet assembly 74 through the inlets 77 and
control features 80. The control features 80 are designed to
produce a pressure drop which is communicated, through the control
jet passageway 76, outlet 78 and nozzle 71, to the mouth 94 of the
sticky switch. The pressure drop "pulls" the fluid flow from the
primary passageway 72 once it enters the sticky switch mouth 94.
The fluid is then directed in the opposite direction from the oil,
toward the "off" passageway 98 of the switch and into the vortex
assembly 100. In the vortex assembly, the less viscous fluid is
directed into the vortex chamber 104 by switch passageway 98 to
produce a relatively tangential spiraled flow, as indicated by the
dashed arrow.
[0037] The fluidic switch assembly 90 extends from the downstream
end of the primary passageway 72 to the inlets into the vortex
assembly 60 (and does not include the vortex assembly). The fluid
enters the fluidic switch from the primary passageway at inlet port
93, the defined dividing line between the primary passageway 72 and
the fluidic switch 90. The fluidic switch overlaps longitudinally
with the downstream portion 79 of the control jet passageway 76,
including the outlet 78 and nozzle 71. The fluid from the primary
passageway flows into the mouth 94 of the fluidic switch where it
is joined and directed by fluid entering the mouth 94 from the
control jet passageway 76. The fluid is directed towards one of the
fluidic switch outlet passageways 96 and 98 depending on the
characteristic of the fluid at the time. The "on" passageway 96
directs fluid into the vortex assembly to produce a relatively
radial flow towards the vortex outlet and a relatively low pressure
drop across the valve assembly. The "off" passageway 98 directs the
fluid into the vortex assembly to produce a relatively spiraled
flow, thereby inducing a relatively high pressure drop across the
autonomous valve assembly. Fluid will often flow through both
outlet passageways 96 and 98, as shown. Note that a fluidic switch
and a sticky switch are distinct types of switch.
[0038] The vortex assembly 100 has inlet ports 106 and 108
corresponding to outlet passageways 96 and 98 of the sticky switch.
The fluid behavior within the vortex chamber 104 has already been
described. The fluid exits through the vortex outlet 102. Optional
vanes or directional devices 110 may be employed as desired.
[0039] More complete descriptions of, and alternative designs for,
the autonomous valve assembly employing control jets can be found
in the references incorporated herein. For example, in some
embodiments, the control jet assembly splits the flow into multiple
control passageways, the ratio of the flow through the passageways
dependent on the flow characteristic, passageway geometries,
etc.
[0040] FIG. 4A-B are flow charts comparing the prior art,
control-jet type of autonomous valve assembly and the sticky-switch
type of autonomous valve assembly presented herein. The sticky
switch type autonomous valve flow diagram at FIG. 4A begins with
fluid, F, flowing through an inlet passageway at step 112, then
through and affected by a biasing mechanism at step 113 which
biases fluid flow into the sticky switch based on a characteristic
of the fluid which changes over time. Fluid then flows into the
sticky switch at step 114 where the fluid flow is directed towards
a selected side of the switch (off or on, for example). No control
jets are employed.
[0041] FIG. 4B is a flow diagram for a standard autonomous valve
assembly. At step 115 the fluid, F, flows through inlet passageway,
then into a fluid selector assembly at step 116. The fluid selector
assembly selects whether the fluid will be produced or not based on
a fluid characteristic which changes over time. Fluid flows through
at least one control jet at steps 117a and 117b and then into a
fluidic switch, such as a bistable switch, at step 118.
[0042] FIG. 5 is a schematic of a preferred embodiment of a sticky
switch type autonomous valve according to an aspect of the
invention. The sticky switch type autonomous control valve 120 has
an inlet passageway 130, a biasing mechanism 140, a sticky switch
assembly 160, and a variable flow resistance assembly, here a
vortex assembly 180.
[0043] The inlet passageway 130 communicates fluid from a source,
such as formation fluid from a screen annulus, etc., to the biasing
mechanism 140. Fluid flow and fluid velocity in the passageway is
substantially symmetric. The inlet passageway extends as indicated
and ends at the biasing mechanism. The inlet passageway has an
upstream end 132 and a downstream end 134.
[0044] The biasing mechanism 140 is in fluid communication with the
inlet passageway 130 and the sticky switch assembly 160. The
biasing mechanism 140 may take various forms, as described
herein.
[0045] The exemplary biasing mechanism 140 has a biasing mechanism
passageway 141 which extends, as shown, from the downstream end of
the inlet passageway to the upstream end of the sticky switch. In a
preferred embodiment, the biasing mechanism 140 is defined by a
widening passageway 142, as shown. The widening passageway 142
widens from a first cross-sectional area (for example, measured
using the width and height of a rectangular cross-section where the
inlet and widening passageways are rectangular tubular, or measured
using a diameter where the inlet passageway and widening
passageways are substantially cylindrical) at its upstream end 144,
to a larger, second cross-sectional area at its downstream end 146.
The discussion is in terms of rectangular cross-section
passageways. The biasing mechanism widening passageway 142 can be
thought of as having two longitudinally extending "sides," a first
side 148 and a second side 150 defined by a first side wall 152 and
a second side wall 154. The first side wall 152 is substantially
coextensive with the corresponding first side wall 136 of the inlet
passageway 130. The second side wall 154, however, diverges from
the corresponding second side wall 138 of the inlet passageway,
thereby widening the biasing mechanism from its first to its second
cross-sectional areas. The walls of the inlet passageway are
substantially parallel. In a preferred embodiment, the widening
angle .alpha. between the first and second side walls 152 and 154
is approximately five degrees.
[0046] The sticky switch 160 communicates fluid from the biasing
mechanism to the vortex assembly. The sticky switch has an upstream
end 162 and a downstream end 164. The sticky switch defines an "on"
and an "off" outlet passageways 166 and 168, respectively, at its
downstream end. The outlet passageways are in fluid communication
with the vortex assembly 180. As its name implies, the sticky
switch directs the fluid flow toward a selected outlet passageway.
The sticky switch can thought of as having first and second sides
170 and 172, respectively, corresponding to the first and second
sides of the biasing mechanism. The first and second side walls 174
and 176, diverge from the first and second biasing mechanism walls,
creating a widening cross-sectional area in the switch chamber 178.
The departure angles .beta. and .delta. are defined, as shown, as
the angle between the sticky switch wall and a line normal to the
inlet passageway walls (and the first side wall of the biasing
mechanism). The departure angle .delta. on the second side is
shallower than the departure angle .beta. on the first side. For
example, the departure angle .beta. can be approximately 80 degrees
while the departure angle .delta. is approximately 75 degrees.
[0047] The vortex assembly 180 has inlet ports 186 and 188
corresponding to outlet passageways 166 and 168 of the sticky
switch. The fluid behavior within a vortex chamber 184 has already
been described. The fluid exits through the vortex outlet 182.
Optional vanes or directional devices 190 may be employed as
desired.
[0048] In use, a more viscous fluid, such as oil, "follows" the
widening. Stated another way, the more viscous fluid tends to
"stick" to the diverging (second) wall of the biasing mechanism in
addition to sticking to the non-diverging (first) wall. That is,
the fluid flow rate and/or fluid velocity distribution across the
cross-section at the biasing mechanism downstream end 146 are
relatively symmetrical from the first to the second sides. With the
shallower departure angle .delta. upon exiting the biasing
mechanism, the more viscous fluid follows, or sticks to, the second
wall of the sticky switch. The switch, therefore, directs the fluid
toward the selected switch outlet.
[0049] Conversely, a less viscous fluid, such as water or natural
gas, does not tend to "follow" the diverging wall. Consequently, a
relatively less symmetric flow distribution occurs at the biasing
mechanism outlet. The flow distribution at a cross-section taken at
the biasing mechanism downstream end is biased to guide the fluid
flow towards the first side 170 of the sticky switch. As a result,
the fluid flow is directed toward the first side of the sticky
switch and to the "off" outlet passageway of the switch.
[0050] FIG. 6 is a graphical representation of a relatively more
viscous fluid flowing through the exemplary assembly. Like parts
are numbered and will not be discussed again. The less viscous
fluid, such as oil, flows through the inlet passageway and into the
biasing mechanism. The oil follows the diverging wall of the
biasing mechanism, resulting in a relatively symmetrical flow
distribution at the biasing mechanism downstream end. The detail
shows a graphical representation of a velocity distribution 196 at
the downstream end. The velocity curve is generally symmetric
across the opening. Similar distributions are seen for flow rates,
mass flow rates, etc.
[0051] Note a difference between the fluidic switch (as in FIG. 3)
and the sticky switch of the invention. An asymmetric exit angle in
the fluidic switch assembly directs the generally symmetric flow
(of the fluid entering the fluidic switch) towards the selected
outlet. The biasing mechanism in the sticky switch creates an
asymmetric flow distribution at the exit of the biasing mechanism
(and entry of the switch), which asymmetry directs the fluid
towards the selected outlet. (Not all of the fluid will typically
flow through a single outlet; it is to be understood that an outlet
is selected with less than all of the fluid flowing
therethrough.)
[0052] FIG. 7 is a graphical representation of a relatively less
viscous fluid flowing through the exemplary assembly. Like parts
are numbered and will not be discussed again. The less viscous
fluid, such as water or natural gas, flows through the inlet
passageway and into the biasing mechanism. The water fails to
follow the diverging wall of the biasing mechanism (in comparison
to the more viscous fluid), resulting in a relatively asymmetrical
or biased flow distribution at the biasing mechanism downstream
end. The detail shows a graphical representation of a velocity
distribution 198 at the downstream end. The velocity curve is
generally asymmetric across the opening.
[0053] The discussion above addresses viscosity as the fluid
characteristic of concern, however, other characteristics may be
selected such as flow rate, velocity, etc. Further, the
configuration can be designed to "select" for relatively higher or
lower viscosity fluid by reversing which side of the switch
produces spiral flow, etc. These variations are discussed at length
in the incorporated references.
[0054] Additional embodiments can be employed using various biasing
mechanisms to direct fluid flow toward or away from a side of the
sticky switch. The use of these variations will not be discussed in
detail where their use is similar to that described above. Like
numbers are used throughout where appropriate and may not be called
out.
[0055] FIG. 8 is a schematic view of an alternate embodiment of the
invention having a biasing mechanism employing wall contour
elements. The inlet passageway 130 directs fluid into the biasing
mechanism 140. The second side 150 of the biasing mechanism is
relatively smooth in contour. The first side 148 of the biasing
mechanism passageway has one or more contour elements 200 are
provided in the first side wall 152 of the biasing mechanism. Here,
the contour elements are circular hollows extending laterally from
the biasing mechanism passageway. As the fluid, F, flows along the
biasing mechanism, the contour elements 200 shift the centerline of
the flow and alter the fluid distribution in the biasing mechanism.
(The distributions may or may not be symmetrical.) In a manner
analogous to refraction of light, the contours seem to add
resistance to the fluid and to refract the fluid flow. This fluid
refraction creates a bias used by the switch to control the
direction of the fluid flow. As a result, a more viscous fluid,
such as oil, flows in the direction of the second side 172 of the
sticky switch, as indicated by the solid arrow. A relatively less
viscous fluid, such as water or natural gas, is directed the other
direction, toward the first side 170 of the sticky switch, as
indicated by the dashed line.
[0056] It will be obvious to those skilled in the art that other
curved, linear, or curvilinear contour elements could be used, such
as triangular cuts, saw-tooth cuts, Tesla fluidic diodes,
sinusoidal contours, ramps, etc.
[0057] FIG. 9 is a detail schematic view of an alternate embodiment
of the invention having a biasing element including contour
elements and a stepped cross-sectional passageway shape. The
biasing mechanism 140 has a plurality of contour elements 202 along
one side of the biasing mechanism passageway 141. The contour
elements 202 here are differently sized, curved cut-outs or hollows
extending laterally from the biasing mechanism passageway 141. The
contour elements affect fluid distribution in the passageway.
[0058] Also shown is another type of biasing mechanism, a step-out
204, or abrupt change in passageway cross-section. The biasing
mechanism passageway 141 has a first cross-section 206 along the
upstream portion of the passageway. At a point downstream, the
cross-section abruptly changes to a second cross-section 208. This
abrupt change alters the fluid distribution at the biasing
mechanism downstream end. The cross-sectional changes can be used
alone or in combination with additional elements (as shown), and
can be positioned before or after such elements. Further, the
cross-section change can be from larger to smaller, and can change
in shape, for example, from circular to square, etc.
[0059] The biasing mechanism causes the fluid to flow towards one
side of the sticky switch for a more viscous fluid and toward the
other side for a less viscous fluid.
[0060] FIG. 9 also shows an alternate embodiment for the sticky
switch outlet passageways 166 and 168. Here a plurality of "on"
outlet passageways 166 direct fluid from the sticky switch to the
vortex assembly 180. The fluid is directed substantially radially
into the vortex chamber 184 resulting in more direct flow to the
vortex outlet 182 and a consequent lower pressure drop across the
device. The "off" outlet passageway 168 of the sticky switch
directs fluid into the vortex chamber 184 substantially
tangentially resulting in a spiral flow in the chamber and a
relatively greater pressure drop across the device than would
otherwise be created.
[0061] FIG. 10 is a schematic view of an alternate embodiment of
the invention having fluidic diode shaped cut-outs as contour
elements in the biasing mechanism. The biasing mechanism 140 has
one or more fluidic diode-shaped contour elements 210 along one
side wall which affect the flow distribution in the biasing
mechanism passageway 141 and at its downstream end. The flow
distribution, which changes in response to changes in the fluid
characteristic, directs the fluid toward selected sides of the
sticky switch.
[0062] FIG. 11 is a schematic view of an alternate embodiment of
the invention having Tesla diodes 212 along the first side 148 of
the fluid passageway 141. The Tesla diodes affect the flow
distribution in the biasing mechanism. The flow distribution
changes in response to changes in the fluid characteristic, thereby
directing the fluid toward selected sides of the sticky switch.
[0063] FIG. 12 is a schematic view of an alternate embodiment of
the invention having a chicane 214, or a section of the biasing
mechanism passageway 141 having a plurality of bends 216 created by
flow obstacles 218 and 220 positioned along the sides of the
passageway. The chicane affects the flow distribution in the
biasing mechanism. The flow distribution changes in response to
changes in the fluid characteristic, thereby directing the fluid
toward selected sides of the sticky switch. In the exemplary
embodiment shown, the flow obstacles 218 along the opposite side
are semi-circular in shape while the flow obstacles 220 are
substantially triangular or ramp-shaped. Other shapes, numbers,
sizes and positions can be used for the chicane elements.
[0064] FIG. 13 is a schematic view of an alternate embodiment of
the invention having a biasing mechanism passageway 141 with a
curved section 222. The curved section operates to accelerate the
fluid along the concave side of the passageway. The curved section
affects flow distribution in the biasing mechanism. The flow
distribution changes in response to changes in the fluid
characteristic, thereby directing the fluid toward selected sides
of the sticky switch. Other and multiple curved sections can be
employed.
[0065] The invention can also be used with other flow control
systems, such as inflow control devices, sliding sleeves, and other
flow control devices that are already well known in the industry.
The inventive system can be either parallel with or in series with
these other flow control systems.
[0066] While this invention has been described with reference to
illustrative embodiments, this description is not intended to be
construed in a limiting sense. Various modifications and
combinations of the illustrative embodiments as well as other
embodiments of the invention will be apparent to persons skilled in
the art upon reference to the description. It is, therefore,
intended that the appended claims encompass any such modifications
or embodiments.
[0067] Further, the invention can be used to select for more
viscous fluids over less viscous fluids or vice versa. For example,
it may be desirable to produce natural gas but restrict production
of water, etc. The following U.S. Patents and Applications for
patent, referenced by Patent Number or Patent Application Serial
Numbers, are each hereby incorporated herein by reference for all
purposes, including providing support for any claimed subject
matter: U.S. patent application Ser. No. 12/700,685, Method and
Apparatus for Autonomous Downhole Fluid Selection with Pathway
Dependent Resistance System; Ser. No. 12/750,476, Tubular Embedded
Nozzle Assembly for Controlling the Flow Rate of Fluids Downhole;
Ser. No. 12/791,993, Flow Path Control Based on Fluid
Characteristics to Thereby Variably Resist Flow in a Subterranean
Well; Ser. No. 12/792,095, Alternating Flow Resistance Increases
and Decreases for Propagating Pressure Pulses in a Subterranean
Well; Ser. No. 12/792,117, Variable Flow Resistance System for Use
in a Subterranean Well; Ser. No. 12/792,146, Variable Flow
Resistance System With Circulation Inducing Structure Therein to
Variably Resist Flow in a Subterranean Well; Ser. No. 12/879,846,
Series Configured Variable Flow Restrictors For Use In A
Subterranean Well; Ser. No. 12/869,836, Variable Flow Restrictor
For Use In A Subterranean Well; Ser. No. 12/958,625, A Device For
Directing The Flow Of A Fluid Using A Pressure Switch; Ser. No.
12/974,212, An Exit Assembly With a Fluid Director for Inducing and
Impeding Rotational Flow of a Fluid; and Ser. No. 12/966,772,
Downhole Fluid Flow Control System and Method Having Direction
Dependent Flow Resistance. Each of the incorporated references
described further details concerning methods and apparatus for
autonomous fluid control.
* * * * *