The present disclosure relates generally to liner hangers and, more particularly, to a fully supported c-ring slip retention system for use in a liner hanger.
When drilling a well, a borehole is typically drilled from the earth's surface to a selected depth and a string of casing is suspended and then cemented in place within the borehole. A drill bit is then passed through the initial cased borehole and is used to drill a smaller diameter borehole to an even greater depth. A smaller diameter casing is then suspended and cemented in place within the new borehole. This is conventionally repeated until a plurality of concentric casings are suspended and cemented within the well to a depth which causes the well to extend through one or more hydrocarbon producing formations.
Rather than suspending a concentric casing from the bottom of the borehole to the surface, a liner is often suspended adjacent to the lower end of the previously suspended casing, or from a previously suspended and cemented liner, so as to extend the liner from the previously set casing or liner to the bottom of the new borehole. A liner is defined as casing that is not run to the surface. A liner hanger is used to suspend the liner within the lower end of the previously set casing or liner.
A running and setting tool disposed on the lower end of a work string may be releasably connected to the liner hanger, which is attached to the top of the liner. The work string lowers the liner hanger and liner into the open borehole until the liner hanger is adjacent the lower end of the previously set casing or liner, with the lower end of the liner typically slightly above the bottom of the open borehole. When the liner reaches the desired location relative to the bottom of the open borehole and the previously set casing or liner, a setting mechanism is conventionally actuated to move an anchoring element (e.g., slips) on the liner hanger from a compressed position to an expanded position and into engagement with the previously set casing or liner. Thereafter, when set down weight is applied to the anchoring body, the anchoring element is set to support the liner.
The liner hanger anchoring element can include a radially expandable and contractable c-ring with slip teeth formed about its outer and inner edge and a frustoconical tapered surface for supporting the liner within the previously set casing or liner. Typically, the c-ring slip (or anchoring body) is held in a compressed position within a recess in the body of the liner hanger while the liner hanger is lowered through the borehole. The c-ring slip is then moved out of the recess in the body of the liner hanger, and into its expanded position.
Unfortunately, the c-ring slip can sometimes become dislodged from the recess in the liner hanger body while the liner hanger is being lowered through the borehole, thereby unintentionally expanding the anchoring element before the liner hanger is ready to be set. This premature expansion of the anchoring element can cause undesirable delays, since the liner hanger assembly must be removed from the wellbore and the anchoring element reset.
For a more complete understanding of the present disclosure and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
Illustrative embodiments of the present disclosure are described in detail herein. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation specific decisions must be made to achieve developers' specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure. Furthermore, in no way should the following examples be read to limit, or define, the scope of the disclosure.
Certain embodiments according to the present disclosure may be directed to a liner hanger with a fully supported c-ring slip retention system and associated method for retaining and extracting the c-ring slip to set the liner hanger.
Liner hangers typically retain a c-ring slip in a compressed position under a lip of the liner hanger body as the liner hanger is being lowered downhole. Once the liner hanger reaches a desired location within a previously set casing or liner, existing systems often utilize tie-bars to remove the c-ring slip from the lip to set the liner hanger. Unfortunately, such tie-bars are susceptible to buckling failure modes when impact forces act on the c-ring slip. In addition, the c-ring slip can sometimes become dislodged from the lip in the liner hanger body while the liner hanger is being lowered through the borehole, thereby prematurely and unintentionally releasing the slip or anchoring element.
The disclosed embodiments address the deficiencies of previous liner hanger designs by providing an improved c-ring slip retention system, which allows for a “fully supported c-ring slip”. The c-ring slip retention system may use an axially movable support sleeve with a support ring for securing the c-ring slip against a retention lip of the liner hanger body. In some embodiments, the liner hanger body and the c-ring slip may be constructed with specifically keyed profiles that enable a tight fit and distribution of impact forces from the c-ring slip to the rest of the liner hanger. The disclosed retention system also prevents the c-ring slip from prematurely dislodging from the liner hanger body while the liner hanger is being lowered through a borehole.
The c-ring slip retention system may also include anti-rotation features that prevent the c-ring slip from rotating relative to the liner hanger body. Such anti-rotation features may include shoulders on the support sleeve designed to engage with corresponding slots formed in the c-ring slip to eliminate or minimize rotation of the c-ring slip.
In the disclosed liner hanger system and method, the support sleeve may be axially displaced to extract the c-ring slip from the liner hanger body, allowing the c-ring slip to expand and set the liner hanger. Such actuation of the support sleeve in the axial direction may simultaneously unlock the c-ring slip from its position within the retention lip and disengage the anti-rotation features. In some embodiments, extracting the c-ring slip from the retention lip may involve moving the support ring relative to the c-ring slip to enable the c-ring slip to compress and move past the locking profile on the retention lip. In certain embodiments, disengaging the anti-rotation features may involve axially moving the support sleeve such that the anti-rotation shoulders on the support sleeve are withdrawn from the corresponding slot walls and into expanded portions of the slots.
The disclosed c-ring slip retention system and method for extraction of the c-ring slip may facilitate a more reliable liner hanger that prevents premature release of the slip or anchoring element. The retention system and anti-rotation features keep the c-ring slip in a desired axial, radial, and angular position prior to extraction. The system enables effective transfer of large axial/radial forces and torques that might act on the c-ring slip while the liner hanger is being lowered downhole, while facilitating extraction of the c-ring slip via the application of a relatively small actuation force.
Turning now to the drawings,
In the illustrated embodiment, the c-ring slip retention system 14 may include a retention lip 24 formed in the liner hanger body 12, a support sleeve 26, and a support ring 28. The retention lip 24 is a lip formed around the liner hanger body 12, and the lip 24 extends in a direction parallel to the liner hanger longitudinal axis 22. The retention lip 24 defines a cavity between the lip 24 and the rest of the liner hanger body 12 for receiving and holding the c-ring slip 16 when the c-ring slip 16 is in a compressed state. The support sleeve 26 may include one or more sleeve portions that are disposed within the liner hanger body 12 and axially movable relative to the liner hanger body 12. The support ring 28 is a ring disposed around the support sleeve 26.
A more detailed view of the c-ring slip retention system 14 is illustrated in
The second part of the c-ring slip retention system 14 is the support ring 28 disposed against an inner surface 58 of the c-ring slip 16. The support ring 28 may bias the c-ring slip 16 radially outward and into a secure engagement (via interlocking profiles 50 and 56) with the inner wall 54 of the retention lip 24.
In the illustrated embodiment, the retaining profile 50 of the c-ring slip 16 may include two shoulders 60, and the complementary profile 56 on the retention lip 24 may be sized to receive the corresponding shoulders 60 when the c-ring slip retention system 14 is locked. As illustrated, the two shoulders 60 may have different widths from each other. These “widths” may be measured in a direction parallel to the longitudinal axis 22 of the liner hanger 10. For example, a first (front) shoulder 60A disposed closer to the extended edge of the retention lip 24 may have a smaller width than a second (back) shoulder 60B located further from the extended edge of the retention lip 24. This arrangement may prevent the back shoulder 60B from becoming caught in the portion of the retention lip profile 56 sized to interface with the smaller front shoulder 60A as the c-ring slip 16 is extracted from the retention lip 24. In other embodiments, the two shoulders 60 may have different heights from each other to achieve a similar effect.
Although two shoulders 60 are illustrated in
The shoulders 60 may span the circumference of the c-ring slip 16, so as to provide a relatively large area of interference between the c-ring slip 16 and the retention lip 24. In some embodiments, as shown in
Turning back to
The c-ring slip retention system 14 may prevent the c-ring slip 16 from being pulled out of the retention lip 24 if, for example, debris catches on the outer edge (e.g., slip teeth 18) of the c-ring slip 16 while the liner hanger 10 is being lowered through a borehole. If a force of impact acts on the c-ring slip 16 (e.g., in direction 62), the force would be transmitted into the retention lip 24 via the keyed interlocking profiles 50 and 56. The axial force (62) may then be converted to a radial load on the support ring 28 and a tension load on the liner hanger body 12. This transfer of forces within the c-ring slip retention system 14 may prevent premature release of the c-ring slip 16 from the retention lip 24. It should be noted that the disclosed slip retention system 14 does not utilize tiebars like conventional liner hangers. Therefore, the slip retention system 14 eliminates buckling as a failure mode by allowing the axial impact force 62 to be converted into radial force that is transmitted into the liner hanger body 12 via the support ring 28.
Turning back to
As mentioned above, the disclosed c-ring slip retention system 14 may include anti-rotation features that substantially prevent the c-ring slip 16 from rotating relative to the longitudinal axis of the liner hanger while the liner hanger is tripping in a borehole. Such anti-rotation features may be particularly suitable for use in “slim-line” liner hangers. However, other conventional sized liner hangers may benefit from the anti-rotation features as well.
To that end, the c-ring slip 16 and the anti-rotation portion 114 of the support sleeve 26 may each include anti-rotation shoulders 116, as shown. The c-ring slip 16 may include opposing anti-rotation shoulders 116 on opposite sides (or walls) of the T-slot 112, while the anti-rotation sleeve portion 114 may include anti-rotation shoulders 116 on opposite edges thereof to interface with the anti-rotation shoulders 116 of the T-slot 112.
Any torsional load (e.g., in a rotational direction 118) imparted on the c-ring slip 16 may be transmitted through the anti-rotation shoulders 116 into the support sleeve 26 and into the dovetail slots 90 of the liner hanger body 12, thereby preventing further rotation of the c-ring slip 16. In this manner, the anti-rotation features 110 substantially prevent rotation of the c-ring slip 16 relative to the support sleeve 26. The anti-rotation features 110 may allow only a minimal rotation of the c-ring slip 16 (i.e., just far enough for the anti-rotation shoulder 116 of the T-slot 112 to engage the shoulder 116 of the anti-rotation sleeve portion 114).
In
While the liner hanger 10 is being moved downhole in the locked position, any torsional loads (e.g., rotational impact forces) acting on the c-ring slip 16 may be easily transmitted through the support sleeve 26 to the large liner hanger body 12. Specifically, a rotational impact force applied to the c-ring slip 16 may be transferred from the c-ring slip 16 to the anti-rotation portion 114 of the support sleeve 26 via the flat anti-rotation shoulders 116. The support sleeve 26 may be disposed within and connected to the liner hanger body 12 (not shown) through the support sleeve fingers 26A-E extending into dovetail slots (90 of
The support sleeve 26 may also transmit rotational impact forces from the c-ring slip 16 to the liner hanger body 12 through one or more stingers 132. As illustrated, each support sleeve portion 26 may include a stinger 132 extending longitudinally from the anti-rotation portion 114 of the support sleeve 26. As shown in
A detailed description of the method for unlocking the disclosed c-ring slip retention system 14 to extract the c-ring slip 16 will now be provided. In the locked/compressed position described above with reference to
In some embodiments, a hydraulically actuated piston on a liner hanger running tool may pull axially uphole on the support sleeve 26, thereby moving the support sleeve in an axial direction. Actuating the support sleeve 26 in the axial direction may unlock the c-ring slip retention system 14 and the anti-rotation features 110 at approximately the same time. A relatively small amount of force may be applied to actuate the support sleeve 26 to unlock the system. The slip retention system 14, however, may be able to transmit a much greater amount of force from the c-ring slip 16 to the liner hanger body 12 when the c-ring slip 16 is retained in the locked position.
Turning again to
The slip retention system 14 is shown in the compressed position in
After compressing the c-ring slip 16, the running tool may continue to stroke the support sleeve 26 in the axial direction 150 until the outwardly biased c-ring slip 16 has been completely extracted from the retention lip 24 of the liner hanger body 12. The c-ring slip 16 is shown in the fully extracted position in
The disclosed slip retention system 14 may provide a mechanical lock for radial deflections, as well as the anti-rotation features 110 for angular deflections. The system may ensure that any axial impact exerted on the c-ring slip 16 is absorbed by the interlocking profile at the retention lip 24 and converted into a radial collapse force that is ultimately transmitted to the liner hanger body 12 via the support sleeve 26. Torsional loads acting on the c-ring slip 16 may also be transmitted into the liner hanger body 12 via the anti-rotation features 110 (i.e., T-slots 112 and anti-rotation shoulders on the support sleeve 26). Both mechanical lock systems may be deactivated, and the c-ring slip 16 extracted from the retention lip 24, via a single axial movement of the support sleeve 26 actuated, for example, by a single hydraulic piston on a liner hanger running tool.
Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the following claims.
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Entry |
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Office Action issued in related GB Application No. 1701925.8, dated May 25, 2017 (4 pages). |
Number | Date | Country | |
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20170226815 A1 | Aug 2017 | US |