Inserts with Swellable Elastomer Seals for Side Pocket Mandrels
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.
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1. Field of the Invention
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.
2. Description of the Related Art
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.
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.
Other flow control devices are often used within side pocket mandrels, including water flood valves and chemical injection valves.
SUMMARY OF THE INVENTIONIn 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.
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:
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
The inventive sealing concept may also be used in conjunction with standard gas lift valves as well as dummy valve inserts.
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.
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.
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.
Type: Application
Filed: Nov 17, 2008
Publication Date: May 20, 2010
Applicant: Baker Hughes Incorporated (Houston, TX)
Inventors: Samuel L. Wildman (Kingwood, TX), James H. Kritzler (Pearland, TX), Walt R. Chapman (Kingwood, TX), Paul W. Atkins (Magnolia, TX)
Application Number: 12/271,997
International Classification: E21B 23/03 (20060101); E21B 33/127 (20060101); E21B 23/01 (20060101);