U.S. patent application number 13/758575 was filed with the patent office on 2013-06-06 for downhole fluid recirculation valve.
This patent application is currently assigned to STELLARTON TECHNOLOGIES INC.. The applicant listed for this patent is STELLARTON TECHNOLOGIES INC.. Invention is credited to Grant GEORGE, Jordan JAMES, Geoff STEELE.
Application Number | 20130140040 13/758575 |
Document ID | / |
Family ID | 41050544 |
Filed Date | 2013-06-06 |
United States Patent
Application |
20130140040 |
Kind Code |
A1 |
GEORGE; Grant ; et
al. |
June 6, 2013 |
DOWNHOLE FLUID RECIRCULATION VALVE
Abstract
A downhole valve for insertion in a production tubing string
permits recirculation of fluid pumped into the casing annulus. The
valve includes a cylindrical housing defining an opening, an
internal mandrel disposed within the housing, defining a central
bore and defining an opening, a valve between the housing and the
mandrel, wherein said valve opens to allow fluid communication from
the mandrel central bore to the annulus space in response to a
pressure differential between the mandrel central bore and the
annular space, and biasing means for biasing the valve in a closed
position. The valve may be set within a completion string by
wireline techniques
Inventors: |
GEORGE; Grant; (Calgary,
CA) ; STEELE; Geoff; (Calgary, CA) ; JAMES;
Jordan; (Calgary, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
STELLARTON TECHNOLOGIES INC.; |
Calgary |
|
CA |
|
|
Assignee: |
STELLARTON TECHNOLOGIES
INC.
Calgary
CA
|
Family ID: |
41050544 |
Appl. No.: |
13/758575 |
Filed: |
February 4, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12398651 |
Mar 5, 2009 |
8387710 |
|
|
13758575 |
|
|
|
|
Current U.S.
Class: |
166/386 |
Current CPC
Class: |
Y10T 137/2572 20150401;
E21B 34/06 20130101; E21B 34/14 20130101; E21B 34/08 20130101; Y10T
137/271 20150401 |
Class at
Publication: |
166/386 |
International
Class: |
E21B 34/06 20060101
E21B034/06 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 5, 2008 |
CA |
2623902 |
Claims
1. A method of setting a downhole fluid recirculation valve within
a completion string, comprising the steps of placing a completion
string comprising a tubing sliding sleeve within a wellbore,
setting an upper packoff and a lower packoff to define a valve
zone, running the valve within the completion string to a position
within the valve zone by a wireline.
2. The method of claim 1 wherein the valve comprises: (a) a
cylindrical housing defining an opening; (b) an internal mandrel
disposed within the housing, defining a central bore and defining
an opening; (c) a valve disposed between the housing and the
mandrel, wherein said valve is moveable between an open position
which allows fluid communication from the mandrel central bore
through the housing opening and the mandrel opening, wherein said
valve is responsive to a pressure differential between the mandrel
central bore and the valve environment; and (d) a spring for
biasing the valve in a closed position, wherein the spring
comprises a coil spring concentrically disposed within the housing,
and around the mandrel.
3. The method of claim 2 wherein the valve comprises a sliding
member having a sealing portion at its distal end, wherein said
sealing portion covers the mandrel opening when the valve is in its
closed position.
4. The method of claim 3 wherein the sliding member is a
cylindrical member concentrically disposed within the housing and
around the mandrel.
5. The method of claim 4 wherein the spring comprises a coil spring
concentrically disposed within the housing, and around the
mandrel.
6. The method of claim 2 wherein the valve further comprises a
pressure equalization chamber formed between the housing and the
mandrel, a first portion of which is in fluid communication with
the mandrel inner bore, and a second portion of which is in fluid
communication with the annulus, and further comprising a valve
extension piston which engages the upper end of the valve which
comprises an upper end which reciprocates in the pressure
equalization chamber between the first and second portions.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 12/398,651 filed on Mar. 5, 2009 entitled
"Downhole Fluid Recirculation Valve", the contents of which are
incorporated herein by reference.
FIELD OF INVENTION
[0002] The present invention relates to a fluid recirculation
valve, and more particularly to a downhole gas recirculation valve
used in well completions.
BACKGROUND
[0003] A well completion refers to the process of making an oil or
gas well ready for production. Generally, this process involves
running in production tubing, and perforating or stimulating as
required.
[0004] Some gas producing wells use plungers to lift production gas
and liquids to the surface by providing a seal within the
production tubing and utilizing downhole pressure to lift the
plunger. In some cases, a plunger lift may be enhanced by
increasing downhole pressure. In a relatively non-porous formation,
gas or fluid may be injected into the casing-tubing annulus, which
in turn returns up through the production tubing. However, in such
techniques cannot be used in more porous formations as the fluid
will be lost into the formation.
[0005] It is known to provide means for recirculating fluid from
the annular space through to the production tubing, however such
means have invariably involved a check valve which forms part of
the tubing string. The disadvantage to this completion is the check
valve is permanent and cannot be serviced. Once the useful lift of
this valve is reached it must be disabled with the use of a tubing
patch or an expensive well re-completion.
[0006] Therefore, there is a need in the art for an improved
downhole valve which permits one way flow of fluids from the
annular space to the tubing string while mitigating the
disadvantages of the prior art.
SUMMARY OF INVENTION
[0007] The present invention relates to a gas recirculation valve
which may be installed during a well completion and which is
installed through the production tubing. As a result, installation,
removal and servicing may be accomplished without expensive
re-completions. This valve also provides a means for retrieval and
servicing via wireline intervention.
[0008] In one aspect, the invention may comprise a downhole valve
for insertion in a production tubing string and a casing string,
wherein an annular space is defined between the tubing and the
casing, said valve comprising: [0009] (a) a cylindrical housing
defining an opening; [0010] (b) an internal mandrel disposed within
the housing, defining a central bore and defining an opening;
[0011] (c) a valve disposed between the housing and the mandrel,
wherein said valve is moveable between an open position which
allows fluid communication from the mandrel central bore to the
annular space through the housing opening and the mandrel opening,
wherein said valve is responsive to a pressure differential between
the mandrel central bore and the annular space; and [0012] (d) a
spring for biasing the valve in a closed position.
[0013] In another aspect, the invention may comprise a method of
recirculating fluid in a well comprising a production tubing string
and a casing string, wherein an annular space is defined between
the tubing and the casing, said method comprising the steps of:
[0014] (a) installing a downhole fluid recirculation valve into a
completion string which forms part of the production tubing string,
wherein said valve is disposed between two packoffs isolating a
valve zone between them, said valve zone is in fluid communication
with the annular space; [0015] (b) installing isolation means for
isolating the annular space below the isolation means from the
annular space above the isolation means; and [0016] (c) pumping
fluid under pressure into the annular space such that the valve
opens and the fluid passes into the production tubing string and
returns to the surface.
[0017] The recirculating gas may be used to drive an intermitting
plunger in the production tubing string or it may be used to
maintain a critical or minimum gas flow rate in the tubing.
[0018] In another aspect, the invention comprises a method of
setting a downhole fluid recirculation valve within a completion
string, comprising the steps of placing a completion string
comprising a tubing sliding sleeve within a wellbore, setting an
upper packoff and a lower packoff to define a valve zone, running
the valve within the completion string to a position within the
valve zone by a wireline.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Exemplary embodiments are illustrated in referenced figures
of the drawings. It is intended that the embodiments and figures
disclosed herein are to be considered illustrative rather than
restrictive.
[0020] FIG. 1 is a schematic disclosing the different sections of a
well-bore.
[0021] FIG. 2 is a schematic of the upper section of a well-bore
disclosed in FIG. 1.
[0022] FIG. 3 is a schematic of the flow control section of a
well-bore disclosed in FIG. 1.
[0023] FIG. 4 is a schematic of the lower section of the well-bore
disclosed in FIG. 1.
[0024] FIG. 5 is a schematic of the well-bore perforation section
disclosed in FIG. 1.
[0025] FIG. 6 is a perspective view of an embodiment of the current
invention.
[0026] FIG. 7 is a schematic of the free flow control valve of the
invention in an open position with the spring in a compressed
state.
[0027] FIG. 8 is a schematic of the free flow control valve of the
invention in a closed position with the spring in a relaxed state.
FIG. 8A shows a detail of the pressure equalization chamber.
DETAILED DESCRIPTION
[0028] The present invention relates to a method and apparatus for
recirculating fluids in a wellbore having an annular space between
a casing string and a tubing string. When describing the present
invention, all terms not defined herein have their common
art-recognized meanings. To the extent that the following
description is of a specific embodiment or a particular use of the
invention, it is intended to be illustrative only, and not limiting
of the claimed invention. The following description is intended to
cover all alternatives, modifications and equivalents that are
included in the spirit and scope of the invention, as defined in
the appended claims.
[0029] In one embodiment, the valve (10) described herein is a
completion tool which is part of a completion string, as shown in
FIG. 1. The following description is of one embodiment of the tool
and its use in a gas re-circulation completion.
[0030] As shown in FIGS. 1 and 2, the valve (10) is installed as
part of a completion string which includes an upper section (A)
having a landing spring (12) for an intermitter (14), such as an
intermitter described in Applicant's co-owned U.S. Pat. No.
7,188,670. As is well known in the art, the intermitter (14)
travels up and down within the production tubing (1), pushing up
accumulated well fluids to the surface. It is urged upward by
pressure within the production tubing, below the intermitter
(14).
[0031] The various components of the completion string are well
known in the art, and are not intended to be limiting of the valve
of the present invention, unless specifically claimed in that
manner.
[0032] The valve (10) is run into the flow control section (B)
between two wireline conveyed tubing packoffs (16, 18). The upper
velocity tube packoff (16) may be located in upper section (A). The
lower section (C) includes the lower velocity tube packoff (18) and
the velocity tube anchor (20). The upper and lower packoffs (16,
18) isolate the valve zone within the production tubing. The lower
velocity tube (22) hangs from the velocity tube anchor (20) and
ends with a velocity tube isolation valve (28) in the perforation
section (D). The lower velocity tube (22) passes through the tubing
packoff (26) which isolates the annular space from the perforation
section (D).
[0033] The production tubing (1) is in selective fluid
communication with the annular space by means of perforations or a
sliding sleeve (19) which can be opened or closed. The perforations
or sliding sleeve open up the tubing in the valve zone between the
upper and lower packoffs (16, 18). The valve (10) resides in the
valve zone, and may be is run in inside the sliding sleeve (19) on
an upper velocity tube (23).
[0034] Thus fluid communication between the annulus and the
production tubing, above the tubing packoff (26) is controlled by
the sliding sleeve (19) and the valve (10).
[0035] In one embodiment, the valve (10) may be installed above the
sliding sleeve (19) rather than the configuration shown in FIG. 3,
where the valve (10) is disposed below the sliding sleeve (19).
[0036] Produced fluids from the perforation section enters the
tubing (1) through the isolation valve (28) into the lower velocity
tube (22), passes through the valve (10), and upwards through the
upper velocity tube (23) and into the production tubing.
[0037] The valve (10) permits one-way flow of fluids from the
annular space between the tubing (1) and the casing (2), above the
tubing packoff (26), into the tubing. Gas or liquid introduced into
the annular space is isolated from the perforation section (D) by
the tubing packoff (26). As a result, such gas or liquid will
return to the surface by entering the tubing through the valve
(10). Thus, the tubing below the intermitter may be pressurized by
injecting fluids into the annular space and through the valve
(10).
[0038] As shown in FIGS. 6 and 7, the valve (10) itself includes a
housing (50), and a mandrel (52) concentrically disposed within the
housing (50). The mandrel is attached to a top sub (54) which
allows threaded connection to the remainder of the completion
string, which may be run into the production tubing by conventional
wireline techniques. At the lower end of the valve (10), the
mandrel (52) engages the inner surface of the housing. An O-ring
(56) provides a seal between the mandrel and the housing at the
lower end.
[0039] The housing (50) engages a piston sub (58) which connects to
the top sub (54), which connection is sealed with O-ring (61).
[0040] The housing (50) defines a plurality of openings (60) which
are preferably covered by a filter screen (62). The openings
provide fluid communication from outside the housing (50) to a
space (51) between the housing and the mandrel. Within the space
(51) between the housing and the mandrel, a cylindrical member fits
in close tolerance to the outside diameter of the mandrel and acts
as a valve (64). In FIG. 8, the valve (64) is shown in its closed
position, where the lower end of the valve member (64) is seated
against a shoulder (66) formed on the inside of the housing, and
against a shoulder (68) formed on the outside of the mandrel. In
its open position, as shown in FIG. 7, the valve member (64) slides
upwards and opens a fluid passageway between the two shoulders (66,
68). The mandrel defines a number of openings (70) immediately
above shoulder (68) which become exposed when the valve member (64)
travels upwards and opens.
[0041] Therefore, when the valve member (64) is in its open
position, a fluid passageway is created from the annular space,
through housing openings (60), between shoulders (66, 68) and
through mandrel openings (70), and into the production tubing
through the interior of the valve (10).
[0042] When there is no pressure differential between the annulus
and the internal bore of the mandrel, the valve member (64) is
normally maintained in its lowered, closed position by coil spring
(72) which is disposed in the same space between the housing and
the mandrel. The upper end of the spring (72) bears on a spacer
(74) while the lower end of the spring bears on the valve member
(64). As is apparent, the compression of the spring (72) may be
overcome by a pressure differential between the annular space, and
the production tubing. Such fluid pressure urges the valve member
(64) to its open position by overcoming the force of the spring
(72). The force of the spring (72) on the valve (64), and therefore
the pressure differential required to open the valve, may be varied
by varying the strength of the spring or by increasing or
decreasing the size of spacer (74).
[0043] In one embodiment, a valve extension piston (76) is attached
to the upper end of the valve (64) and extends upwards between the
spring (72) and the mandrel (52), and further extends past the
spacer (74) and an isolation ring (78) which provides a seal with
both the housing and the mandrel through the use of O-rings. The
upper end of the valve extension piston (76) reciprocates within a
pressure equalization chamber (80) which is in fluid communication
with the production tubing by way of openings (82) in the mandrel.
The upper end of the valve extension piston (76) does not cover the
openings (82) to the equalization chamber (80). Therefore, the
pressure equalization chamber (80) is always at the same pressure
as that within the production tubing. At the same time, a lower
portion of the pressure equalization chamber is open to the annular
space through openings (83).
[0044] The upper end (84) of the valve extension piston slides
along the inside of the pressure equalization chamber (80) and
includes an O-ring seal (86). In one embodiment, it is preferred to
have a highly polished surface inside the pressure equalization
chamber (80) to limit the friction of the O-ring seal (86) and
ensure the movement of the valve extension piston (76) is
relatively unimpeded.
[0045] When fluid pressure in the annulus is higher than in the
tubing, the pressure equalization chamber (80) utilizes the static
pressure differential to help maintain the valve in a constant full
open state. This system dampens the effect of the gas flow pressure
fluctuations induced by the expansion and contraction of the gas
moving through the lower end of the valve (10).
[0046] An entry guide (88) encircles the housing at its lower end,
and provides a chamfered sub to facilitate running the tools inside
the tubing.
[0047] In operation, fluid such as a gas may be pumped downhole
through the annulus, creating a pressure differential between the
annulus and the production tubing. As a result, the valve (10) will
open and allow fluid to flow into the production tubing. If an
intermitter is installed, the introduced gas will assist in lifting
the intermitter to the surface. When the pressure differential
equalizes, the valve (10) will close.
* * * * *