A method includes providing a retrievable plug assembly at a surface of an oil or gas well, the plug assembly having a seal element that has an original outer diameter. The method also includes stretching the seal element so that the outer diameter is less than the original outer diameter and then placing the plug assembly between first and second zones formed within the tubing string. The method also includes removing any tensile axial load on the seal element so that it shrinks back towards its original outer diameter while positioned between the first and second zones. The method also includes compressing the seal element so that the seal element sealingly engages an inner surface of the tubing string to isolate the first zone from the second zone.

TECHNICAL FIELD

The present disclosure relates generally to a packer assembly used in wells, and specifically, to a retrievable pre-tension packing assembly for mid-expansion applications.

BACKGROUND

After a well is drilled and a target reservoir has been encountered, completion and production operations are performed, which may include running a tubing string downhole within the wellbore. Often, a first zone of the tubing string is isolated from a second zone of the tubing string. In order to isolate the first zone from the second zone, a packing assembly, such as a bridge plug that includes a seal element is extended into the tubing string. The bridge plug is “set” moved into an expanded state such that the seal element sealingly engages an inner surface of the tubing string to isolate the first zone from the second zone.

Often, a seal element is run downhole in a neutral configuration (i.e., undergoing no axial tensile or compression loading) and then expands to contact the inner surface of the tubing string, which often results in a high amount of stress and strain on the seal element. This may result in poor sealing performance and retrievability issues.

The present disclosure is directed to a retrievable pre-tension packing assembly for mid-expansion applications that addresses one or more of the foregoing issues.

DETAILED DESCRIPTION

The foregoing disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” “uphole,” “downhole,” “upstream,” “downstream,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the apparatus in use or operation in addition to the orientation depicted in the figures. For example, if the apparatus in the figures is turned over, elements described as being “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” may encompass both an orientation of above and below. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Referring initially toFIG. 1, a well having a retrievable pre-tension packing assembly is disposed therein from an offshore oil or gas platform that is schematically illustrated and generally designated10. A semi-submersible platform15may be positioned over a submerged oil and gas formation20located below a sea floor25. A subsea conduit30may extend from a deck35of the platform15to a subsea wellhead installation40, including blowout preventers45. In one or more exemplary embodiments, the platform15may have a hoisting apparatus50, a derrick55, a travel block60, a hook65, and a swivel70for raising and lowering pipe strings, such as a substantially tubular, axially extending tubing string75. In one or more exemplary embodiments, a wellbore80extends through the various earth strata including the formation20and has a casing string85cemented therein. In one or more exemplary embodiments, disposed in a substantially horizontal portion of the wellbore80is at least one retrievable pre-tension packing assembly, or bridge plug assembly95, disposed on an inner mandrel100that extends within a passage105formed within the tubing string75. In one or more exemplary embodiments, the tubing string75has an inner diameter of75a.

Even thoughFIG. 1depicts a horizontal wellbore, it should be understood by those skilled in the art that the apparatus according to the present disclosure is equally well suited for use in wellbores having other orientations including vertical wellbores, slanted wellbores, multilateral wellbores or the like. Accordingly, it should be understood by those skilled in the art that the use of directional terms such as “above,” “below,” “upper,” “lower,” “upward,” “downward,” “uphole,” “downhole” and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure, the uphole direction being toward the surface of the well, the downhole direction being toward the toe of the well. Also, even thoughFIG. 1depicts an offshore operation, it should be understood by those skilled in the art that the apparatus according to the present disclosure is equally well suited for use in onshore operations. Further, even thoughFIG. 1depicts a cased hole completion, it should be understood by those skilled in the art that the apparatus according to the present disclosure is equally well suited for use in open hole completions.

In one or more exemplary embodiments, and as illustrated inFIG. 2, the bridge plug assembly95includes gauge rings155and160that are concentrically disposed and axially spaced about the mandrel100. In one or more exemplary embodiments, a seal element or a packing element170is concentrically disposed about the mandrel100and accommodated between the gauge rings155and160. In one or more exemplary embodiments, at least a portion of the gauge rings155and160are concentrically disposed about an exterior surface of the packing element170such that the gauge rings155and160are coupled to the packing element170. In one or more exemplary embodiments, the packing element170includes an elastomer. In one or more exemplary embodiments, the packing element170defines a cross-section and the packing element170extends uninterruptedly throughout the cross-section. In an exemplary embodiment, the bridge plug assembly95also includes a backup assembly (not shown). In one or more exemplary embodiments, each of the gauge rings155and160has an interior surface that forms teeth that correspond with teeth formed on the exterior surface of the packing element170. However, the gauge rings155and160may be coupled to the packing element in a variety of ways.

With reference toFIG. 3and with continuing reference toFIGS. 1-2, in one or more embodiments, a method of operating the bridge plug95is generally referred to by the reference numeral200and may include assembling the bridge plug95while in a first configuration at step205; applying tension to the packing element170to place the bridge plug95in a second configuration at step210; positioning the bridge plug95downhole between a first zone and a second zone at step215; allowing the bridge plug95to return to a third configuration at step220; applying axial compression to the packing element170to place the bridge plug95in a fourth configuration thereby isolating the first zone from the second zone at step225; and removing the bridge plug95from between the first zone and the second zone at step230. In one or more exemplary embodiments, the packing element170has a first configuration, a second configuration, a third configuration, and a fourth configuration that corresponds with the first configuration, the second configuration, the third configuration, and the fourth configuration of the plug assembly95.

At the step205, the bridge plug95is assembled or manufactured while in the first configuration. As illustrated inFIG. 2, while the bridge plug95is in the first configuration, the packing element170has a first outer diameter235and a first length240. In one or more exemplary embodiments, the first outer diameter235is an original outer diameter. In one or more exemplary embodiments, the gauge rings155and160are axially spaced such that the packing element170is not stretched or compressed. Thus, the first configuration is a neutral configuration (i.e., a configuration in which the packing element170undergoes no axial tension or axial compression). In one or more exemplary embodiments, the first outer diameter235is greater than the inner diameter75aof the tubing string75. Thus, the packing element170has an outer diameter larger than the inner diameter of the tubing string while the bridge plug95is in the first configuration. However, in one or more exemplary embodiments, the first outer diameter235is equal to or less than the inner diameter75aof the tubing string.

At the step210, tension is applied to the packing element170to move the bridge plug95into the second configuration, as illustrated inFIG. 4. In one or more exemplary embodiments, the bridge plug95is in the second configuration prior to deploying the bridge plug95downhole, or placing it in the passage105formed by the tubing string75. In one or more exemplary embodiments, the ring gauge166and160are axially spaced such that the packing element170is under tension and stretched in the axial direction. In one or more exemplary embodiments, the ring gauge155applies a tensile axial load on the packing element170by pulling a portion of the packing element170in a direction indicated by numeral245inFIGS. 4-6and the ring gauge160applies a tensile axial load on the packing element170by pulling a portion of the packing element in a direction indicated by numeral250inFIGS. 4-6. In one or more exemplary embodiments and when the bridge plug95is in the second configuration, the packing element170has a second outer diameter255and a second length260. As the packing element170is stretched in the axial direction, the second outer diameter255is less than the first outer diameter235. In one or more exemplary embodiments, the second outer diameter255is less than the inner diameter75aof the tubing string75. In one or more exemplary embodiments, the second outer diameter255is less than an outer diameter of the ring gauge155or an outer diameter of the ring gauge160or both. Thus, the bridge plug95may be extended and moved within the tubing string75while the bridge plug95is in the second configuration, as the packing element170is spaced from an inner surface of the tubing string75when extended within the tubing string75. In one or more exemplary embodiments, the packing element170is under a tensile axial load while the bridge plug95is in the second configuration to reduce the outer diameter of the packing element170. In one or more exemplary embodiments, packing element170is stretched while the bridge plug95is in the second configuration such that the second length260is greater than the first length240.

At the step215, the bridge plug95is positioned downhole between a first zone of passage105and a second zone of the passage105. In one or more exemplary embodiments, the bridge plug95is in the second configuration when positioned downhole between the first zone and the second zone. In an exemplary embodiment and when the bridge plug95is extended within the tubing string75while in the second configuration, the packing element170is spaced from the inner surface of the tubing string75.

At the step220, the bridge plug95is moved into the third configuration, as illustrated inFIG. 5. In one or more exemplary embodiments, the bridge plug95is allowed to “relax” to the third configuration. That is, the tensile axial load is removed from the packing element170so that the packing element170is in the neutral configuration. In one or more exemplary embodiments, the tensile axial load on the packing element170is eliminated or reduced such that the packing element170and the bridge plug95moves towards the first configuration. Thus, in one or more exemplary embodiments, the packing element170expands radially to a third outer diameter260and the length shrinks to a third length262. In one or more exemplary embodiments, the third length262is less than the second length260. As the first outer diameter235of the packing element170while the bridge plug95is in the first configuration is greater than the inner diameter75aof the tubing string75, the third outer diameter260may equal to the inner diameter75awhile the bridge plug95, and the packing element170, are in the third configuration. That is, the inner surface of the tubing string75limits the radial expansion of the packing element170. However, in one or more other exemplary embodiments, the outer diameter260may be less than the inner diameter75a. Nevertheless, the third outer diameter260of the packing element170while the bridge plug95is in the third configuration is greater than the second outer diameter255of the packing element170while the bridge plug95is in the second configuration. In one or more exemplary embodiments, the packing element170has the third outer diameter260without undergoing any axial compression. This allows for the packing element170to be at least partially set without undergoing stress relating to compression. In one or more exemplary embodiments, the tensile axial load may be removed from the packing element170by adjusting the axially spacing of the gauge rings155and160.

At the step225, axial compression is applied to the packing element170to move the bridge plug95into the fourth configuration, as illustrated inFIG. 6. In one or more exemplary embodiments, the gauge ring155moves in the direction250illustrated inFIGS. 4-6and the gauge ring160moves in the direction245illustrated inFIGS. 4-6to compress the packing element170(i.e., axial compression). In one or more exemplary embodiments, the packing element170and bridge plug95is considered “set” while in the fourth configuration, as the axial compression of the packing element170results in a portion, or a larger portion, of the exterior surface of the packing element170contacting the inner surface of the tubing string75. In one or more exemplary embodiments, the exterior surface of the packing element170sealingly engages the inner surface of the tubing string75to fluidically isolate the first zone of the passage105from the second zone of the passage105. In one or more exemplary embodiments and when the third outer diameter260is this equal to the inner diameter75aof the tubing75, the packing element170deforms while the bridge plug95is in the fourth configuration such that a larger portion of the exterior surface of the packing element170has the third outer diameter260. In other exemplary embodiments and when the third outer diameter260is less than the inner diameter75aof the tubing string75, then the packing element170deforms while the bridge plug95is in the fourth configuration to have a fourth outer diameter that is equal to the inner diameter75aof the tubing string75. In one or more exemplary embodiments, the packing element170has a fourth length265that is less than the third length262, the second length260, and the first length240. In one or more exemplary embodiments, the amount of axial compression to move the bridge plug95from the third configuration to the fourth configuration results in significantly less stress in the packing element170while the bridge plug95is in the fourth configuration because the packing element170, while in the neutral configuration, is already partially set when the bridge plug95is in the third configuration.

At the step230, the bridge plug95is retrieved from downhole. In one or more exemplary embodiments, axial compression is removed from the packing element170by axially adjusting the gauge rings155and160and the bridge plug95is removed from the wellbore. In one or more exemplary embodiments, the steps225,220,215,210may be performed in reverse to retrieve the bridge plug95from downhole.

In one or more exemplary embodiments, the bridge plug95is a medium expansion plug. In one or more exemplary embodiments, the bridge plug95is a medium expansion plug and is adapted to be exposed to high downhole pressures.

In one or more exemplary embodiments, the bridge plug95is a pre-tension mid-expansion plug that is retrievable. In one or more exemplary embodiments, the bridge plug95expands radially in response to an axial compression force. In one or more exemplary embodiments, the bridge plug95is partially set when in the third configuration. In one or more exemplary embodiments, the packing element170is under little or no compression forces when in the third configuration. Thus, the packing element170is under little or no stress when in the third configuration. Considering the packing element170is under no little or no stress when partially set, the stress created within the bridge plug95and/or the packing element170when transitioning to the fourth configuration is low. Thus, low stresses when in the fully set configuration, or the fourth configuration, results in enhanced sealing performance of the packing element170and easy retrieval of the bridge plug95from the wellbore.

In one or more exemplary embodiments, an axial force and axial movement is generally perpendicular to a radial force and radial movement.

In one or more exemplary embodiments, the packing element170, the gauge rings155and160, and the method200may be applied to any variety of downhole tools, such as bridge through plugs, packers, etc.

In several exemplary embodiments, while different steps, processes, and procedures are described as appearing as distinct acts, one or more of the steps, one or more of the processes, and/or one or more of the procedures may also be performed in different orders, simultaneously and/or sequentially. In several exemplary embodiments, the steps, processes and/or procedures may be merged into one or more steps, processes and/or procedures. In several exemplary embodiments, one or more of the operational steps in each embodiment may be omitted. Moreover, in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. Moreover, one or more of the above-described embodiments and/or variations may be combined in whole or in part with any one or more of the other above-described embodiments and/or variations.

Thus, a packing element has been described. Embodiments of the packing assembly may generally include a packing assembly adapted to extend within a pre-existing structure, the pre-existing structure defining a circumferentially extending inner surface defining an inner diameter, the packing assembly includes an elongated base pipe and a seal element disposed on the base pipe. For any of the foregoing embodiments, packing assembly may include any one of the following elements, alone or in combination with each other:The packing assembly is radially shrinkable from a first configuration to a second configuration and radially expandable from the second configuration to a third configuration.When the packing assembly in the first configuration, the seal element has a first diameter that is greater than the inner diameter.When the packing assembly in the second configuration, the seal element has a second diameter that is less than the first diameter and less than the inner diameter.The second outer diameter is less than an outer diameter of at least one of the first and second gauge rings.When the packing assembly is in the third configuration, the seal element has a third diameter that is greater than the second configuration and equal to or less than the inner diameter.The packing assembly is a plug assembly.The pre-existing structure is a tubing string.The packing assembly further includes axially-spaced first and second gauge rings, each of the first and second gauges ring being disposed on the base pipe and coupled to the seal element.When the packing assembly extends within the tubing string and the packing assembly is in the second configuration, the first and second gauge rings are spaced axially such that the seal element is under a tensile axial load.When the packing assembly extends within the tubing string and the packing assembly is in the third configuration, the seal element is in a neutral configuration and the third diameter is equal to or less than the inner diameter.When the packing assembly extends within the tubing string and the packing assembly is in a fourth configuration, the first and second gauge rings are spaced axially such that the seal element is under axial compression and the seal element sealingly engages the inner surface.When the packing assembly is in the first configuration, the seal element is in a neutral configuration.The packing assembly is in the first configuration at a surface of a well.The packing assembly is in the second configuration at a surface of the well.The packing assembly is a retrievable packing assembly.The seal element is comprised of one or more elastomer materials.The seal element defines a cross-section.The one or more elastomer materials extends uninterruptedly throughout the cross-section.When the packing assembly extends within the tubing string and the packing assembly is in the fourth configuration, the elastomer sealing engages the inner surface of the tubing string.

Thus, a method has been described. Embodiments of the method may generally include providing a plug assembly in a first configuration at a surface of a well in which a tubing string extends, the plug assembly including: an elongated base pipe adapted to extend within the tubing string; and a seal element disposed on the base pipe and defining a first outer diameter while in the first configuration; applying a tensile axial force to the seal element to move the plug assembly to a second configuration, the seal element defining a second outer diameter while in the second configuration; disposing the plug assembly in the tubing string; positioning the plug assembly while in the second configuration between a first zone and a second zone of a passage defined by the tubing string; removing the tensile axial force while the plug assembly is positioned between the first zone and the second zone such that the plug assembly moves to a third configuration, the seal element defining a third outer diameter while in the third configuration; and compressing the seal element while the plug assembly is in the third configuration to move the plug assembly to a fourth configuration such that the seal element is expanded in a radially outward direction to sealingly engage an inner surface of the tubing string. For any of the foregoing embodiments, the method may include any one of the following, alone or in combination with each other:While the plug assembly is in the fourth configuration, the seal element fluidically isolates the first zone of the passage from the second zone of the passage.The first configuration and the third configuration are associated with the seal element being in a neutral configuration.The plug assembly further includes first and second gauge rings, each of the first and second gauge rings being disposed on the base pipe and coupled to the seal element, the seal element being disposed between the first and second gauge rings.The seal element has a first length while the plug assembly is in the first configuration.Applying the tensile axial force to the seal element axially stretches the seal element such that the seal element has a second length while the plug assembly is in the second configuration, the second length being greater than the first length.Removing the tensile axial force while the plug assembly is positioned between the first zone and the second zone causes the seal element to have a third length while the plug assembly is in the third configuration, the third length being less than the second length.Compressing the seal element while the plug assembly is in the third configuration to move the plug assembly to the fourth configuration causes the seal element to have a fourth length while the plug assembly is in the fourth configuration, the fourth length being less than the second length and less than the first length.The inner surface of the tubing string defines an inner diameter.The first outer diameter is greater than the inner diameter.The second outer diameter is less than the inner diameter.The second outer diameter is less than an outer diameter of at least one of the first and second gauge rings.The fourth outer diameter is equal to the inner diameter.Retrieving the plug assembly from within the well.The seal element is comprised of one or more elastomer materials.The seal element defines a cross-section.The one or more elastomer materials extends uninterruptedly throughout the cross section.The plug assembly is a retrievable plug assembly.Compressing the seal element while the plug assembly is in the third configuration to move the plug assembly to the fourth configuration causes the elastomer to sealing engage the inner surface of the tubing string.

The foregoing description and figures are not drawn to scale, but rather are illustrated to describe various embodiments of the present disclosure in simplistic form. Although various embodiments and methods have been shown and described, the disclosure is not limited to such embodiments and methods and will be understood to include all modifications and variations as would be apparent to one skilled in the art. Therefore, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Accordingly, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.