US20070044977A1

US20070044977A1 - Packer

Info

Publication number: US20070044977A1
Application number: US11/309,003
Authority: US
Inventors: James Hendrickson; Karen Grosser; Yanmei Li
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 2005-08-23
Filing date: 2006-06-07
Publication date: 2007-03-01
Also published as: GB2429473B; NO20063750L; CA2556517A1; GB2429473A; CA2556517C; GB0616459D0

Abstract

A packer that is usable with a well includes a resilient seal element and a support member. The resilient seal element is adapted to radially expand in response to the longitudinal compression of the element. The support member is at least partially surrounded by the seal element and is adapted to radially expand with the seal element to support the element. The support sleeve is substantially harder than the seal element.

Description

This application claims the benefit pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 60/595,997 entitled, “PACKER ELEMENT WITH SUPPORT,” filed on Aug. 23, 2005, which is hereby incorporated in reference in its entirety.

BACKGROUND

The invention generally relates to a packer.
Hydrocarbon fluids, such as oil and natural gas, are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion involves the design, selection, and installation of equipment and materials in or around the wellbore for conveying, pumping, or controlling the production or injection of fluids. After the well has been completed, production of oil and gas can begin.
In such well completion operations, packers are used to prevent fluid flow through an annulus formed by a tubing within the well and the wall of the wellbore or a casing. The packer is generally integrally connected to the tubing, using, for example, means such as a threaded connection, a ratch-latch assembly, or a J-latch, all of which are well known in the art. The tubing/packer connection generally establishes the seal for the inner radius of the annulus. The seal for the outer radius of the annulus is generally established by a deformable element such as rubber or an elastomer. A compressive force is generally applied to the deformable element, causing it to extrude radially outward. The element extends from the outer portion of the packer to the wellbore wall or casing and seals between those structures.

SUMMARY

In an embodiment of the invention, a packer that is usable with a well includes a resilient seal element and a support member. The resilient seal element is adapted to radially expand in response to the longitudinal compression of the element. The support member is at least partially surrounded by the seal element and is adapted to radially expand with the seal element to support the element. The support sleeve is substantially harder than the seal element.
In another embodiment of the invention, a technique that is usable with a well includes compressing a resilient seal element to cause the seal element to radially expand. The technique includes in concert with the radial expansion of the seal element, deforming a material that is substantially harder than the seal element to support the seal element.
Advantages and other features of the invention will become apparent from the following drawing, description and claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic diagram of a well according to an embodiment of the invention.
FIG. 2 is a schematic diagram depicting a seal assembly of the packer of FIG. 1 according to an embodiment of the invention.
FIG. 3 depicts the seal assembly when the packer is set according to an embodiment of the invention.
FIGS. 4, 5, 6 and 7 depict seal assemblies according to other embodiments of the invention.

DETAILED DESCRIPTION

A packer is a device that is used in an oilfield well to form a seal for purposes of controlling production, injection or treatment. The packer is lowered downhole into the well in an unset state, and once in the appropriate position downhole, the packer is set, which means a seal of the packer radially expands to seal off an annular space. As an example, for a mechanically-set packer, a tubular string that extends from the surface to the packer may be moved pursuant to a predefined pattern to set the packer. For a hydraulically-set packer, fluid inside the tubular string may be pressurized from the surface, to create a tubing pressure differential to set the packer.
In its set state, the packer anchors itself to the casing wall of the well (or to the wellbore wall in an uncased or open well) and forms a seal in the annular region between the packer and the interior surface of the casing wall. This seal subdivides the annular region to form an upper annular region above the packer that is sealed off from a lower annular region below the packer. The packer also forms a seal for conduits that are inserted through the packer between the upper and lower annular regions. As examples, one of these conduits may communicate production fluid from a production zone that is located below the packer, one of the conduits may communicate control fluid through the packer, one of the conduits may house electrical wiring for a submersible pump, allow production or injection through two different reservoir zones, and so forth.
FIG. 1 depicts a well 10 (a subterranean or subsea well) that includes a packer 20 in accordance with an embodiment of the invention. The packer 20 may be connected to a tubular string 16 that extends downhole into the well. The packer 20 forms an annulus seal with the interior surface of a wall of a casing string 12 that circumscribes the packer 20 and lines a wellbore 11. The wellbore 11 may be uncased in some embodiments of the invention. Additionally, the wellbore 11 may be a vertical or a lateral wellbore, depending on the particular embodiment of the invention.
The packer 20 includes at least one seal assembly 24 to form the annular seal and at least one set of slips 22 to anchor the packer 20 to the casing string 12. In this manner, when run into the well, the seal assembly 24 and the slips 22 are radially retracted to allow passage of the packer 20 through the central passageway of the casing string 12. However, when the packer 20 is in the appropriate downhole position, the packer 20 is set to place the packer 20 in a state in which the seal assembly 24 and slips 22 are radially expanded. When radially expanded, the slips 22 grip the interior surface of the wall of the casing string 12 to physically anchor the packer 20 in position inside the well. The radial expansion of the seal assembly 24, in turn, seals off the annular space between the string 16 and the casing string 12 to form a sealed annular region above the seal assembly 24 and a sealed annular region below the seal assembly 24.
In some embodiments of the invention, the packer 20 may be hydraulically-actuated for purposes of controlling the packer 20 from the surface of the well to set the packer 20. This means that pressure may be communicated through fluid inside the string 16 to the packer 20. In response to this pressure reaching a predefined threshold level, pistons (not shown in FIG. 1) move to radially expand the slips 22 and apply compressive forces on the seal assembly 24 to radially expand the assembly 24. A retention mechanism of the packer 20 serves to hold the packer 20 in the set state when the pressure that is used to set the packer 20 is released.
One or more mandrels 21, or tubular members, may extend through the packer 20 for purposes of providing communicating paths through the packer 20. Depending on the particular application of the packer 20, a particular mandrel 21 may contain one or more communication paths, such as paths to communicate production fluid, electrical lines, or control fluid through the packer 20. For example, in a particular application, a single mandrel 21 may extend through the packer 20 for purposes of communicating production fluid from a tubular string 23 located below the packer 20 to the string 16 located above the packer 20. However, in other applications, more than one mandrel 21 may be extended through the packer 20. Thus, one mandrel 21 may be used for purposes of communicating electrical or hydraulic lines, for example, and another mandrel 21 may be used for purposes of communicating production fluid through the packer 20.
The packer 20 may be retrievable, and thus may include a release mechanism that when engaged, releases the retention mechanism of the packer 20 to radially retract the slips 22 and seal assembly 24 to permit retrieval of the packer 20 to the surface of the well.
The packer 20 establishes two general seals: an interior seal between the interior of the packer 20 and the exterior of the one or more mandrels 21 that are extended through the packer 20 and an exterior seal between the exterior of the packer 20 and the interior surface of the wall of the casing string 12 (or the wellbore wall in alternative embodiments). The seal assembly 24 includes a resilient seal element (such as one or more elastomer or rubber sleeves, or rings) for establishing the seal between the packer exterior and the casing 12 (or wellbore wall).
In general, as the requirements for packer designs tend towards larger and larger inner diameters through the packer, the annular seal element of the packer is forced to become thinner and thinner. Additionally, there may also desire to cover multiple casing weights with one size of packer, leading to larger gaps that must be bridged off by the annular seal element. Bridging off a large gap with a thin element may be very difficult, unless the rubber is supported. Embodiments of the invention that are described herein include a packer that has a resilient seal element, which has a support that is fabricated from a hardened material.
In the context of this application, a “hardened material” means a material that has a substantially greater resistance to deformation relative to the seal element of the packer. For example, in some embodiments of the invention, the hardened material may be a metal that has substantially more resistance to deformation than an elastomer or rubber material that forms the seal element. Alternatively, in accordance with other embodiments of the invention, the hardened material may be a composite or plastic material, which has substantially more resistance to deformation that an elastomer or rubber material that forms the seal element. Furthermore, in accordance with other embodiments of the invention, the hardened material may be a combination of the above-mentioned materials. Thus, many variations are contemplated and are within the scope of the appended claims.
As a more specific example, for some embodiments of the invention, the hardened material is a soft metal, such as low carbon steel or copper, in accordance with some embodiments of the invention. However, in accordance with other embodiments of the invention, the hardened material may be a relatively resilient material. For example, in accordance with some embodiments of the invention, the hardened material may be a metallic spring material. Thus, many variations are possible and are within the scope of the appended claims.
FIG. 2 depicts a more detailed section 50 (see FIG. 1) of the packer 20 in accordance with some embodiments of the invention. As shown in FIG. 2, the packer 20 includes sleeves, or gages 54 and 55 (also called “thimbles”), which are designed to longitudinally compress the seal assembly 24 (which is disposed in between) to radially expand the assembly 24 when the packer 20 is set. It is noted that FIG. 2 depicts the packer 20 in its unset state.
In general, the seal assembly 24 includes a resilient seal element that may be formed from multiple seal sleeves, or rings, such as upper 56, middle 60 and lower 64 seal rings. The seal rings 56, 60 and 64 generally circumscribe the inner mandrel 16 of the packer 20 and may be formed from a rubber or an elastomer material (as examples). It is noted that the seal assembly 24 may include fewer or more seal rings, depending on the particular embodiment of the invention.
As also depicted in FIG. 2, the seal assembly 24 may include upper 88 and lower 90 metallic shoes for purposes of minimizing the longitudinal extrusion of the seal element 24 when the packer 20 is set. In the packer's unset state, the upper shoe 88 generally conforms to the upper edge of the seal ring 56 and is located between the upper edge of the seal ring 56 and the upper gage 54; and the lower shoe 90 generally conforms to the lower edge of the lower seal ring 64 and is located between this lower edge and the lower gage 55.
In addition to the resilient seal element, the seal assembly 24 includes a hardened (relative to the seal rings 56, 60 and 64) support sleeve 80 that is located between the resilient seal element and the mandrel 16. As a more specific example, as depicted in FIG. 2, in some embodiments of the invention, the support sleeve 80 may be located (as an example) between the middle seal ring 60 and the outer surface of the mandrel 16. The support sleeve 80, which may have a substantially thinner radial thickness than the middle seal ring 60 (before the packer 20 is set), is designed to be radially expanded (and deformed) with the seal rings 56, 60 and 64 so that the sleeve 80 supports the seal rings 56, 60 and 64 in their radially-expanded states. Although FIG. 2 depicts the support sleeve 80 as being located radially inside the middle seal ring 60, in accordance with other embodiments of the invention, the support sleeve 80 may longitudinally extend inside all or part of the upper 56 and lower 64 seal rings (as another example). Therefore, many variations are possible and are within the scope of the appended claims.
The support sleeve 80 may or may not be bonded to the middle seal ring 60, depending on the particular embodiment of the invention. For embodiments of the invention in which the support sleeve 80 is bonded to the middle seal ring 60, all or only part of the outer surface of the support sleeve 80 may be bonded to the inner surface of the middle seal ring 60. It is noted that depending on the particular embodiment of the invention, the support sleeve 80 may be bonded to all, part or none of the upper 56 and lower 64 seal rings.
In some embodiments of the invention, the support sleeve 80 includes an annular crimped section 82 at its longitudinal midpoint, which radially extends away from the outer surface of the mandrel 16. The crimped section 82 configures the support sleeve 80 to bend at the section 82 during the radial expansion of the seal assembly 24, as depicted in FIG. 3, which shows a section 95 of FIG. 2 when the packer 20 is set. Referring to FIG. 3, in the radially expanded state of the seal assembly 24, the seal rings 56, 60 and 64 are radially expanded and deformed to at least partially contact the inner surface of the casing 12. As also shown in FIG. 3, the support sleeve 80 is also radially expanded and deformed to support the seal rings 56, 60 and 64. The shoes 88 and 90 minimize longitudinal extrusion of the seal element, in this state of the packer 20.
Referring back to FIG. 2, in accordance with some embodiments of the invention, the region between the inner surface of the crimped section 82 and the outer surface of the mandrel 16 may be a void space. However, in accordance with other embodiments of the invention, this space may be filled with a seal element that partially or totaling conforms to the boundaries of the space before the packer 20 is set.
FIG. 4 depicts an exemplary section 100 of another packer in accordance with another embodiment of the invention. The section 100 is to be compared to the corresponding section 95 of the packer 20. In general, the packer has the same overall design as the packer 20, except the seal assembly of this packer includes a single seal ring 124 (made from elastomer or rubber, for example) and an inner o-ring 110 behind a support sleeve 112 (made from a hardened material relative to the seal ring 124). The support sleeve 112 extends over the entire inner surface of the seal ring 124. The support ring 112 also includes a crimped section 114 that, in the unset state of the packer 20, radially extends away from the outer surface of the mandrel 16. The crimped section 114 creates a void 116 that receives the o-ring seal 110. Other seals may be located inside the space 116, in accordance with other embodiments of the invention.
Referring to FIG. 5, in accordance with other embodiments of the invention, another packer, which is illustrated by an exemplary section 150 (to be compared to sections 95 and 100), includes expandable rings 160 and 178 that are located between the gages and a single seal ring 190. More specifically, an upper expandable ring 160 is located between an upper gage 154 and an upper edge of the seal ring 190. The upper gage 154 may include a sloped, or beveled, surface 156 for purposes of slidably engaging with the upper expandable seal ring 160. Likewise, a lower expandable seal ring 178 may be located between a lower gage 164 and the lower surface of the seal ring 190. Similar to the upper gage 154, the lower gage 164 includes a sloped, or beveled, surface 166 for purposes of slidably engaging the lower expandable ring 178.
As also shown in FIG. 5, the packer includes a support sleeve 180 (made from a hardened material) that extends over the entire surface of the seal ring 190 for purposes of providing support to the ring 190 for the set state of the packer. The seal ring 180 includes a crimped section 182 that is predisposed to cause the support ring 180 to radially expand at the section 182 during the setting of the packer, similar to the support rings 80 and 112 that are described above.
As yet another variation, FIG. 6 depicts an exemplary section 200 of a packer in accordance with another embodiment of the invention. As shown, the packer includes garter springs that are located between the gages and the seal assembly. More specifically, an upper garter spring 210 is located between an upper gage 202 and the upper edge of a seal ring 230. A lower garter spring 212 is located between the upper edge of a lower gage 220 and the lower edge of the seal element 230. Additionally, the packer includes a support sleeve 232 (made from a hardened material) that is located over the entire inner surface of the seal ring 230 between the seal ring 230 and the outer surface of the mandrel 16; and the sleeve 232 includes a crimped portion 234 to predispose the sleeve 232 to radially expand at the section 234 during the setting of the packer.
As yet another example, FIG. 7 depicts an exemplary section 250 of a packer in accordance with another embodiment of the invention. The section 250 is similar to the section 50 (see FIG. 2) (with like reference numerals being used), with the following differences. In particular, the packer includes support rings 260 and 270 that are located at the ends of the seal assembly 24 for purposes of minimizing longitudinal extrusion of the packer's seal element. The support ring 260 is located between the upper shoe 88 and the upper gage 54; and the lower ring 270 is located between the lower gage 55 and the shoe 90.
Each of the rings 260 and 270 has a V-shaped cross-section and provides support to minimize longitudinal extrusion of the seal element (seal rings 56, 60 and 64) when the packer is set. More specifically, when the packer is set, the V-shaped rings 260 and 270 each flatten to be substantially horizontal and rise above the gauge diameter, thereby minimizing the extrusion gap and supporting the seal element.
While the present invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.

Claims

1. A packer usable with a well, comprising:

a resilient seal element adapted to radially expand in response to a longitudinal compression of the seal element; and

a support member at least partially surrounded by the seal element and being substantially harder than the seal element, the support member adapted to radially expand with the seal element to support the seal element.

2. The packer of claim 1, wherein the support member comprises a sleeve circumscribed by the seal element.

3. The packer of claim 1, wherein the support member has a first radial thickness that is substantially smaller than a second radial thickness of the seal element.

4. The packer of claim 1, wherein the support has substantially more resistance to deformation than the seal element.

5. The packer of claim 1, wherein the seal element comprises at least one of a rubber and an elastomer.

6. The packer of claim 1, wherein the member comprises a metal.

7. The packer of claim 1, wherein the support member is bonded to the resilient seal element.

8. The packer of claim 1, further comprising:

an inner tubular member of the packer having an outer surface,

wherein the support member comprises first regions that closely adhere to the outer surface before the longitudinal compression of the seal element and a second region that extends radially away from the outer surface before the longitudinal compression of the seal element.

9. The packer of claim 1, further comprising:

another seal element at least partially circumscribed by the support member.

10. The packer of claim 1, further comprising:

a gage adapted to longitudinally compress the seal element; and

at least one expandable seal assembly located between the gage and the seal element.

11. The packer of claim 1, further comprising:

a gage adapted to longitudinally compress the seal element; and

at least one spring located between the gage the seal element.

12. The packer of claim 1, further comprising:

a gage adapted to longitudinally compress the seal element; and

at least one radially expandable ring located between the gage and the seal element.

13. A method usable with a well, comprising:

providing a resilient seal element adapted to radially expand in response to longitudinal compression of the seal element; and

radially inside the seal element, disposing a support member adapted to radially expand with the seal element to support the seal element, the support member being significantly harder than the seal element.

14. The method of claim 13, further comprising:

selecting the support member to have substantially more resistance to deformation than the resilient seal element.

15. The method of claim 13, wherein the resilient seal element comprises at least one of a rubber and an elastomer.

16. The method of claim 15, wherein the support member comprises a metal.

17. The method of claim 13, further comprising:

bonding the support member to the seal element.

18. A method usable with a well, comprising:

compressing a resilient seal element to cause the seal element to radially expand; and

in concert with the radial expansion of the seal element, deforming a material that is substantially harder than the seal element to support the seal element.

19. The method of claim 18, wherein the support member has substantially more resistance to deformation than the seal element.

20. The method of claim 18, wherein the seal element comprises at least one of a rubber and an elastomer.

21. The method of claim 13, wherein the member comprises at least one of a metal, a composite and a plastic.

22. A system usable with a well, comprising:

a string; and

a packer connected to the string, the packer comprising:

23. The system of claim 22, wherein the support member has substantially more resistance to deformation than the seal element.