Patent Application
20120186830
The present invention relates generally to packer assemblies usable in a bore in a subterranean formation and, more particularly (although not necessarily exclusively), to packer assemblies that are capable of withstanding relatively large load forces and that are retrievable from the bore.
Packer assemblies can be used in a wellbore to separate the wellbore into one or more zones. A packer assembly can include a packer element capable of providing an annular seal between a tubing string and a casing string, a slip that can retain the packer assembly in a position by gripping the casing string, a wedge that supports the slip, and a mandrel that provides support to the assembly.
Initially, the slip can be positioned closer to the mandrel such that it is unsupported by the wedge to facilitate running the packer assembly downhole. In a set or operation position, or otherwise after running the packer assembly downhole, the wedge supports the slip toward an inner diameter of the casing string. The slip can grip the inner wall of the casing string to retain the packer assembly in position.
It can be desirable to remove a packer assembly from the wellbore. A packer assembly can be removed after the wedge unsupports the slip. Various techniques have been developed to allow the wedge to unsupport the slip. The techniques include modifying a slip tooth angle and providing a collapsible wedge.
The slip tooth angle can be modified such that a passive angle of the tooth matches an angle on the wedge to allow the slip to be pulled off the wedge easier. Modifying the slip tooth angle, however, can decrease the load bearing capability of the slip and wedge and can result in damage to the casing. It can also result in debris being introduced downhole due to shearing that may be needed to release the wedge from the slip. A collapsible wedge can be made from a material that is not rigid or can include grooves that allow it to collapse downhole to release from supporting the slip. A collapsible wedge, however, may collapse prior to a desired time or debris can settle around the wedge, preventing collapse.
Other techniques include pulling the slip from the wedge, which can result in debris due to sheared metal and can be difficult in view of the outward force applied to the slip by the wedge.
Therefore, packer assemblies are desirable that can provide sufficient load bearing performance and that can be removable from the bore.
Certain aspects and embodiments of the present invention are directed to packer assemblies capable of providing desired load performance and responding to a force in a downhole direction to disengage from a position to allow the packer assemblies to be retrievable from a bore. In some embodiments, a mandrel can include a groove capable of receiving a load device when the mandrel is in a release position. When the load device is received by the groove, the wedge can be capable of responding to the force in the downhole direction by un-supporting the slip. In some embodiments, the wedge can be configured with a mechanism that prevents or reduces slip re-setting.
One feature relates to a packer assembly capable of being disposed in a bore of a subterranean formation. The packer assembly can include a load device, a wedge, and a mandrel. The wedge can cooperate with the load device to support a slip toward a casing string. The slip can engage the casing string. The mandrel can be moved to a release position. The mandrel can include a groove configured to receive the load device in the release position. The wedge can respond to a force in a downhole direction by un-supporting the slip to allow the slip to disengage from the casing string in the release position.
Another feature relates to a method that includes running a packer assembly into a bore of a subterranean formation. The packer assembly includes a wedge and a mandrel. The wedge cooperates with a load device to support a slip toward a casing string such that the slip engages an inner diameter of the casing string. The method also includes moving the mandrel up-hole to a release position at which a groove in the mandrel receives the load device. The wedge responds to a force in a downhole direction by un-supporting the slip to allow the slip to disengage from the inner diameter of the casing string.
Another feature relates to a packer assembly capable of being disposed in a bore in a subterranean formation. The packer assembly includes a slip and a wedge. The wedge can, in a set or operation position, support the slip toward a casing string to allow the slip to engage an inner diameter of the casing string and support a load on the packer assembly in a downhole direction. The wedge can, in a release position, respond to a force in the downhole direction by allowing the slip to disengage the inner diameter of the casing string.
These illustrative aspects and features are mentioned not to limit or define the invention, but to provide examples to aid understanding of the inventive concepts disclosed in this application. Other aspects, advantages, and features of the present invention will become apparent after review of the entire application.
Certain aspects and embodiments of the present invention relate to packer assemblies capable of providing desired load bearing performance and of being retrieved from a bore in a subterranean formation. A packer assembly according to some embodiments can include a wedge that can support a load on the packer assembly in a downhole direction in a set or operation position and respond to a force in a downhole direction by un-supporting the slip in a release position. The unsupported slip is configured to disengage from a casing string, allowing the packer assembly to be removed from the bore. In some embodiments, the wedge is configured to separate from the slip to prevent slip re-setting.
These illustrative examples are given to introduce the reader to the general subject matter discussed here and are not intended to limit the scope of the disclosed concepts. The following sections describe various additional embodiments and examples with reference to the drawings in which like numerals indicate like elements, and directional descriptions are used to describe the illustrative embodiments but, like the illustrative embodiments, should not be used to limit the present invention.
A tubing string 112 extends from the surface within wellbore 102. The tubing string 112 can provide a conduit for formation fluids to travel from the substantially horizontal section 106 to the surface. Packer assemblies 114, 116 are positioned with the tubing string 112 in the horizontal section 106. Other components (not shown), such as production tubing, screens, inflow control devices, can be positioned in the wellbore 102. Packer assemblies 114, 116 can provide annular seals between the tubing string 112 and the casing string 108 to define zones 118, 120. One or both packer assemblies 114, 116 can provide desired load performance and be retrievable from the wellbore 102.
Although
Various types of packer assemblies can be used, including packer assemblies capable of disengaging from a casing string after experiencing a force in the same direction as load bearing forces that the packer assemblies are configured to support.
The mandrel 212 can allow hydrocarbon fluid to flow from a hydrocarbon-bearing formation to a conduit defined by a tubing string. In some embodiments, the mandrel 212 is an integrated part of a tubing string. In other embodiments, the mandrel 212 is separate from, but rigidly coupled to, the tubing string. In the set or operation position, the mandrel 212 can support the load device 210 and the device 214. After operation, the mandrel 212 is capable of being cut or sheared during retrieval initiation and pulled up.
The mandrel 212 in
When the load device 210 is received by the first groove 222, the wedge 206 is at least partially unsupported in a downhole direction by the load device 210 and the element support 208. In some embodiments, the wedge 206 is completely unsupported. When the device 214 is received by the second groove 224, the wedge 206 is at least partially unsupported in a radial direction.
In some embodiments, the wedge groove 216 is configured to allow the device 214 received in the second groove 224 to be removed from overlapping the wedge 206. For example, the device 214 in the second groove 224 can be moved from under the wedge 206 to a position that is not under the wedge 206. In some embodiments, the wedge groove 216 can be defined by an end 226 that does not extend to the mandrel 212 such that the device 214 in the second groove 224 can be removed from overlapping the wedge 206.
After moving the mandrel 212 up-hole, a load can be applied to the tubing string to move the mandrel 212 downhole to a second release position, as depicted in
Although
In a set or operation position as depicted in
After operation, the mandrel 312 can be cut or sheared during retrieval initiation and pulled up-hole, towards the surface. The mandrel 312 includes a groove 322 that is capable of receiving the load device 310. As the mandrel 312 is pulled up-hole, the groove 322 aligns with load device 310 and receives load device 310, as depicted in
In other embodiments, a spring is provided, alternatively or additionally to the atmospheric chamber 316. For example, the spring can be positioned between the wedge 306 and a portion of the element support 308 and configured to bias the wedge 306 until the load device 310 un-supports the wedge 306.
Packer assemblies according to some embodiments can include wedges that are configured to prevent slip re-setting, particularly if a load is set down on the packer assemblies subsequent to retrieval initiation.
Packer assembly 402 includes a slip 404, a wedge 406, an element support 408, a load device 410, and a mandrel 412. The wedge 406 can support the slip 404 toward a casing string 418 in a set or operation position, as depicted in
The packer assembly can include a supporting device 414 that can be positioned in a wedge groove 416. The mandrel 412 can support the wedge 406 through supporting device 414. Supporting device 414 may be any device that is capable of cooperating with the mandrel 412 to support the wedge 406. Examples of supporting device 414 include (but are not limited to) a support ring, a sleeve, a load ring, a snap ring, a set of lugs, a pin, a collet, and a body lock.
The mandrel 412 includes a first groove 420 and a second groove 422. The first groove 420 is capable of receiving the load device 410. The second groove 422 is capable of receiving the supporting device 414.
The wedge 406 includes a collet 424.
After the mandrel 412 is cut or sheared during retrieval initiation, the mandrel 412 is pulled up-hole to a first release position at which the second groove 422 receives the supporting device 414, as shown in
The mandrel 412 can be pulled up-hole to a second release position, as depicted in
The mandrel 412 can be pulled up-hole to a third release position, as depicted in
The mandrel 412 can be pulled up-hole to a fourth release position, as depicted in
Although packer assembly 402 is depicted as having the supporting device 414, packer assemblies according to other embodiments do not use a supporting device. For example, an outer diameter of a mandrel can be enlarged in certain portions of the mandrel to provide support to a collet portion of a wedge and/or reduced in certain other portions that can un-support the collet portion.
The foregoing description of the embodiments, including illustrated embodiments, of the invention has been presented only for the purpose of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Numerous modifications, adaptations, and uses thereof will be apparent to those skilled in the art without departing from the scope of this invention.
