U.S. patent application number 12/271997 was filed with the patent office on 2010-05-20 for inserts with swellable elastomer seals for side pocket mandrels.
This patent application is currently assigned to Baker Hughes Incorporated. Invention is credited to Paul W. Atkins, Walt R. Chapman, James H. Kritzler, Samuel L. Wildman.
Application Number | 20100122819 12/271997 |
Document ID | / |
Family ID | 42170736 |
Filed Date | 2010-05-20 |
United States Patent
Application |
20100122819 |
Kind Code |
A1 |
Wildman; Samuel L. ; et
al. |
May 20, 2010 |
Inserts with Swellable Elastomer Seals for Side Pocket Mandrels
Abstract
Improved inserts for use in side pocket mandrels which include
one or more annular sealing elements that are formed of an
elastomeric material that swell in response to heat or fluid
saturation. When the insert is emplaced within a side pocket
mandrel, the swellable elastomer can then be swelled, using either
heat or fluid saturation, to cause the sealing element(s) to expand
and seal against the seal bore of the side pocket mandrel.
Inventors: |
Wildman; Samuel L.;
(Kingwood, TX) ; Kritzler; James H.; (Pearland,
TX) ; Chapman; Walt R.; (Kingwood, TX) ;
Atkins; Paul W.; (Magnolia, TX) |
Correspondence
Address: |
SHAWN HUNTER
P.O Box 270110
HOUSTON
TX
77277-0110
US
|
Assignee: |
Baker Hughes Incorporated
Houston
TX
|
Family ID: |
42170736 |
Appl. No.: |
12/271997 |
Filed: |
November 17, 2008 |
Current U.S.
Class: |
166/386 ;
166/117.6; 166/187 |
Current CPC
Class: |
E21B 43/123 20130101;
E21B 23/03 20130101 |
Class at
Publication: |
166/386 ;
166/187; 166/117.6 |
International
Class: |
E21B 23/03 20060101
E21B023/03; E21B 33/127 20060101 E21B033/127; E21B 23/01 20060101
E21B023/01 |
Claims
1. An insert for placement within a side pocket mandrel in a
wellbore production string, the gas lift insert comprising: an
insert body; a sealing element disposed upon the insert body, the
sealing element being substantially formed of an elastomeric
material that is swellable from a first, reduced-size, condition to
a second, enlarged-size condition.
2. The insert of claim 1 wherein the insert comprises a dummy gas
lift valve.
3. The insert of claim 1 wherein the insert comprises a gas lift
valve that is operable to transmit gas.
4. The insert of claim 1 wherein the sealing element is swellable
from the first condition to the second condition in response to
fluid saturation by a swelling fluid.
5. The insert of claim 4 wherein the sealing element is swellable
from the first condition to the second condition in response to
fluid saturation by water.
6. The insert of claim 4 wherein the sealing element is swellable
from the first condition to the second condition in response to
fluid saturation by hydrocarbon fluid.
7. The insert of claim 1 wherein the sealing element is swellable
from the first condition to the second condition in response to
heating.
8. An assembly for incorporation within a production tubing string,
the assembly comprising: a side pocket mandrel for incorporation
into a wellbore production string, the side pocket mandrel
comprising: a mandrel body; a primary flowbore defined within the
mandrel body; a side pocket defined within the mandrel body, the
side pocket being in fluid communication with the primary flowbore;
an insert that is removably disposed within the side pocket, the
insert comprising: an insert body that is shaped and sized to
reside within the side pocket; and a sealing element disposed upon
the insert body, the sealing element being substantially formed of
an elastomeric material that is swellable from a first,
reduced-size, condition to a second, enlarged-size condition.
9. The assembly of claim 8 wherein the insert comprises a dummy gas
lift valve.
10. The assembly of claim 8 wherein the sealing element is
swellable from the first condition to the second condition in
response to fluid saturation.
11. The assembly of claim 8 wherein the sealing element is
swellable from the first condition to the second condition in
response to fluid saturation by water.
12. The assembly of claim 8 wherein the insert comprises a dummy
gas lift valve.
13. A method of sealing an insert within a seal bore of a side
pocket mandrel, the method comprising the steps of: disposing the
insert within the seal bore; and expanding a swellable elastomeric
sealing element to form a seal between the insert and the seal
bore.
14. The method of claim 13 wherein the sealing element is expanded
by application of heat and a swelling fluid to the sealing
element.
15. The method of claim 14 wherein the swelling fluid comprises
water.
16. The method of claim 14 wherein the swelling fluid comprises
hydrocarbon fluid.
17. The method of claim 13 wherein the sealing element is expanded
by application of heat.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates generally to devices and methods for
forming seals within tubular members. In particular aspects, the
invention relates to devices and methods for sealing inserts within
a side pocket mandrel.
[0003] 2. Description of the Related Art
[0004] Gas lift arrangements are used to improve the rate of
production of hydrocarbons from a well by enhancing flow through a
production tubing string. Gas lift valves are inserts that are
typically removably emplaced in side pocket mandrels in a
production string. Gas is then injected into the annulus
surrounding the production string. The gas is then transmitted by
the gas lift valves from the annulus to the flowbore of the
production tubing string. Gas lift arrangements are described in
U.S. Pat. No. 7,360,602 entitled "Barrier Orifice Valve for Gas
Lift" issued to Kritzler et al. and U.S. Pat. No. 6,810,955
entitled Is "Gas Lift Mandrel" issued to Roth et al. These patents
are owned by the assignee of the present application and are hereby
incorporated by reference.
[0005] Dummy gas lift valves are inserts that are placed into a gas
lift side pocket mandrel to entirely close off flow through the
side pocket mandrel. Typically, dummy gas lift valves employ stacks
of generally v-shaped elastomeric seals (i.e., v-rings) to form a
fluid seal against a surrounding seal bore of the side pocket
mandrel. The v-ring seals are energized to seal by differential
pressure, which isolates fluid communication through the side
pocket mandrel. When the seal bores of the side pocket mandrel get
eroded or otherwise damaged, the v-rings are no longer able to
fully seal and prevent pressure integrity loss.
[0006] Other flow control devices are often used within side pocket
mandrels, including water flood valves and chemical injection
valves.
SUMMARY OF THE INVENTION
[0007] In preferred embodiments, the invention provides improved
inserts for use in side pocket mandrels and methods of sealing such
inserts within side pocket mandrels. In preferred embodiments, the
insert includes an insert body that carries one or more annular
sealing elements that are formed of an elastomeric material that
swells in response to heat or fluid saturation. When the insert is
emplaced within a side pocket mandrel, the swellable elastomer can
then be swelled, using either heat or fluid saturation, to cause
the sealing element(s) to expand and seal against the seal bore of
the side pocket mandrel. In one preferred embodiment, the insert is
a dummy gas lift valve which will block fluid flow through the side
pocket. In an alternative embodiment, the insert is a gas lift
valve which selectively transmits gas from the surrounding annulus
into the primary flowbore of the gas lift mandrel. In still other
embodiments, the insert is another flow control device, such as a
chemical injection valve or a water flood valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The advantages and further aspects of the invention will be
readily appreciated by those of ordinary skill in the art as the
same becomes better understood by reference to the following
detailed description when considered in conjunction with the
accompanying drawings in which like reference characters designate
like or similar elements throughout the several figures of the
drawing and wherein:
[0009] FIG. 1 is a side, one-quarter cross-sectional view of an
exemplary dummy gas lift valve constructed in accordance with the
present invention.
[0010] FIG. 2 is a side, cross-sectional view of an exemplary side
pocket mandrel containing a dummy valve constructed in accordance
with the present invention.
[0011] FIG. 3 is a side, cross-sectional view of the side packet
mandrel and dummy valve shown in FIG. 2, now with the dummy valve
having been sealed within.
[0012] FIG. 4 is a detail cross-sectional view depicting a sealing
element in its unexpanded state.
[0013] FIG. 5 is a detail cross-sectional view depicting the
sealing element of FIG. 4, now in an expanded state.
[0014] FIG. 6 is a side, cross-sectional view of an alternative
embodiment of the invention incorporating a gas lift valve.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] FIG. 1 illustrates an exemplary dummy gas lift valve 10 that
has been constructed in accordance with the present invention. The
dummy valve 10 includes a generally cylindrical valve body 12 which
is preferably made up of an upper body portion 14 and a lower body
portion 16 affixed to one another via a threaded connection 18. The
upper axial end of the valve body 12 presents a threaded portion 20
which permits the dummy valve 10 to be affixed to a running tool.
The valve body 12 preferably carries a pair of annular sealing
members 22, 24 which are fashioned from an elastomeric material.
The sealing members 22, 24 are preferably formed from an
elastomeric material that is physically swellable in response to a
particular stimulus. In a currently preferred embodiment, the
elastomeric material will swell or expand in response to contact
with wellbore fluids, including water and/or hydrocarbon fluids.
Elastomeric materials of this type are described in, for example,
U.S. Pat. No. 5,384,370 issued to Vondracek et al., entitled
"Rubbers Swellable with Water and Aqueous Solutions and the Method
for Producing the Same" and U.S. Pat. No. 4,590,227 issued to
Nakamura et al., entitled "Water-Swellable Elastomer Composition."
Preferably, the sealing members 22, 24 are solid annular rings. In
preferred embodiments, the energizing fluid may be a hydrocarbon
fluid or water, or a mixture of both, depending upon the particular
composition of the sealing element 22, 24. Thus, the sealing
members 22, 24 can be selectively changed from a first,
reduced-size, condition to a second, enlarged size condition.
[0016] FIGS. 2 and 3 depict a section of an exemplary side pocket
mandrel 26 of a type which is well-known in the art. The side
pocket mandrel 26 is typically incorporated into a string of
production tubing within a wellbore. The mandrel 26 has a mandrel
body 28 which defines a primary flowbore 30 therein. The mandrel
body 28 includes threaded upper and lower ends (not shown) which
permit the mandrel body 28 to be affixed to neighboring sections of
a production tubing string in a manner known in the art. A side
pocket 34 is also defined within the mandrel body 28 and is
generally parallel to and in fluid communication with the primary
flowbore 30. The side pocket 34 preferably includes a pair of
cylindrical polished seal bores 38, 40 and an enlarged diameter
portion 42 disposed between the seal bores 38, 40. Lateral gas
injection passages 44 extend through the mandrel body 28 to
interconnect the enlarged diameter portion 42 with the radially
surrounding annulus 36.
[0017] In operation, the dummy valve 10 is inserted into the side
pocket 34 using a running tool in a manner known in the art. The
dummy valve 10 is moved generally to the position depicted in FIG.
2 so that the sealing element 22 is located within the seal bore 38
and the sealing element 24 is located within the seal bore 40. Once
the dummy valve 10 is in this position, the sealing elements 22 and
24 are swelled to cause them to expand radially outwardly and into
sealing contact with the seal bores 38, 40 of the side pocket
mandrel 26. In the event that the seal bores 38, 40 have been
corroded, eroded or otherwise damaged, the expansion of the sealing
members 22, 24 will compensate.
[0018] FIGS. 4 and 5 illustrate in further detail the expansion of
the sealing members 22, 24 to cause them to seal against the
surrounding seal bores 38, 40 by illustrating the upper sealing
member 22 in greater detail. The exemplary seal bore 38 in FIGS. 4
and 5 is shown to include a damaged portion 46 which has resulted
from erosion or physical impact. FIG. 4 depicts the sealing member
22 in an initial, unexpanded condition, immediately following the
dummy insert 10 having been inserted into the side pocket 34.
Following insertion, the sealing member 22 is activated to move to
its expanded condition depicted in FIG. 5 so that the sealing
member 22 expands radially outwardly and against the seal bore 38.
Additionally, the expansion of the sealing member 22 will fill in
the damaged portion 46, as FIG. 5 illustrates. Typically, an
appropriate fluid (water, hydrocarbon, or a mixture thereof) is
used in conjunction with the elevated wellbore temperature to
expand the sealing members 22, 24. The ambient elevated temperature
within the wellbore applies heat to the sealing members 22, 24. In
most cases, reservoir fluid containing hydrocarbons and water will
be present within the flowbore 30, the annulus 36 and the side
pocket 34 when the insert 10 is inserted into the side pocket 34.
This fluid will act as the swelling fluid that will saturate and
will swell the sealing members 22, 24. Preferably also, a swellable
elastomer composition is chosen for the sealing members 22, 24 to
be activated by the reservoir fluid (swelling fluid) within the
wellbore. In cases where the reservoir pressure within the wellbore
cannot support a fluid level to the insertion depth for the insert
10, a plug (not shown) could be placed within the flowbore of the
production tubing string below the side pocket mandrel 26.
Thereafter, a suitable swelling fluid may be flowed from the
surface down through the production tubing string. The swelling
fluid will enter the side pocket 34 and saturate the sealing
members 22, 24 causing them to swell.
[0019] The inventive sealing concept may also be used in
conjunction with standard gas lift valves as well as dummy valve
inserts. FIG. 6 illustrates an alternative embodiment of the
invention wherein the gas lift insert is a gas lift valve 48 which
can be removably emplaced within a side pocket mandrel to cause gas
from the annulus 36 to be transmitted through the side pocket 34
and into the primary flowbore 30 of the side pocket mandrel 26 and,
hence, the production tubing string of which the side pocket
mandrel 26 is a part. A suitable gas lift valves for use as the gas
lift valve 48 include the Model BCO-1.TM. (J.TM., C.TM., CJ.TM.
injection pressure operated gas lift valve which are available
commercially from Baker Oil Tools of Houston, Tex. The gas lift
valve 48 carries sealing elements 50, 52, which are fashioned from
the same swellable elastomeric material as the sealing elements 22,
24 described previously.
[0020] It can be seen that the gas lift inserts 10 and 48 can be
used in conjunction with the gas lift mandrel 26 in order to
provide a gas lift assembly that can be incorporated into a
wellbore production string. The sealing techniques of the present
invention may also be used with a number of other inserts that
might be used within a side pocket mandrel. For example, swellable
sealing elements may be used in conjunction with water flood or
chemical injection valves that are emplaced within a side pocket
mandrel.
[0021] The foregoing description is directed to particular
embodiments of the present invention for the purpose of
illustration and explanation. It will be apparent, however, to one
skilled in the art that many modifications and changes to the
embodiment set forth above are possible without departing from the
scope and the spirit of the invention.
* * * * *