GB2516158A - Anchor slip and seal locking mechanism - Google Patents

Abstract

A lock assembly for a subterranean tool, comprising a mandrel 22 supporting an outer assembly 18 for selective relative movement there between, a lock 24 selectively retaining said mandrel to said outer assembly to selectively prevent operation of the tool in a first position 28, said lock selectively movable to a second position 38 to permit relative movement between said mandrel and said outer assembly for operation of the tool, said lock further moveable to return to said first position from said second position to prevent further operation of the tool. The lock may be actuated by pressure applied in the mandrel, by a potential energy force or by multiple movements of an actuation sleeve.

Description

APPLTCATTON FOR PATENT

Title: Anchor Slip and Seal Locking Mechanism Inventors: Kevin E. Harrington; Gregory L. Hem and Yang Xu

FIELD OF THE TNVENTTON

1000!] The field of the invention is completion methods and more particularly methods employing a packer settable on a liner hanger to test cement integrity by setting down weight followed by release with picking up and locking the packer with hydraulic force to allow string manipulation for subsequent fluid circulation with the packer locked from resetting.

BACKGROUND OF THE INVENTION

100021 With a liner hung to the surrounding tubular it is desirable to do a cement integrity test by setting a packer on top of the liner hanger to isolate the liner hanger for a pressure test on the casing above. One potential problem with doing this is that the differential on the test packer transfers load to the seal on the liner hanger and can overstress the liner that is at the same time supported off the casing just below the liner hanger seal. In essence the liner hanger slips support the hanger seal and the test packer pushes down on the liner hanger seal against the support of the liner hanger slips with the result being a potential overstress of the top of the liner in the vicinity of the liner hanger seal.

100031 To address this problem in the past the test packers being provided also had slips to dig into the casing to take the differential pressure load while isolating the load from the liner hanger seal. However, these packers generally operated mechanically with a j-slot in combination with drag blocks, The presence of drag blocks precluded reciprocation or rotation of the string supporting the test packer during subsequent operations because the drag block would rub the casing wall and erode the wall.

100041 What is needed and provided by the present invention is a way to keep the test packer retracted for run in. The packer is hydraulically unlocked so that subsequent setting down force will extend the slips and set the packer seal for the test packer. The cement integrity test can then be run with the slips set in the casing so that the differential pressure load is not applied to the seal in the liner hanger. This protects the liner hanger from damage by overstressing. At the end of that test the string is picked up to stretch out the packer and to place locking dogs in alignment with a locking groove inside the outer housing. A second ball is dropped on a seat to break a restraint and move a sleeve to put the dogs in a secured position in the respective groove in the housing. This can be done with pressure simply moving a sleeve down or a return spring moving a sleeve up after initial downward movement breaks a shear device. At that point the string from the surface can be rotated or reciprocated as completion fluids are spotted. A circulation sub can have a port open above the test packer to continue with circulation or for reverse circulation while bypassing the liner. Those skilled in the art will more readily understand the present invention from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims.

SUMMARY OF THE INVENTION

[0005] A test packer is lowered to a set liner hanger in a locked position that prevents the seal and slips from setting during running in, A first bail is dropped to shift a sleeve to release the grip of dogs to a groove on an outer housing. Setting down weight sets the test packer seal and sets the slips, After the casing integrity pressure test is done the test packer is lifted to again position the groove in the outer housing by the dogs. A second ball lands on the same seat now enlarged due to earlier movement and breaks a retainer on a locking sleeve, A spring return or continued downhole motion of the locking sleeve locks the packer in the run in position.

Subsequent rotation and circulation can take place as completion fluid is circulated in. A circulation port above the packer can be opened optionally for circulation or reversing above the test packer.

BRIEF DESCRIPTTON OF THE DRAWINGS

100061 FIG, I is the run in position for the spring return variation of the present invention; 100071 FIG, 2 is the view of FTG, I with the pressure applied on the first ball to unlock the dogs so that the packer can later set with setting down weight; 100081 FIG. 3 is the view of FIG. 2 with the slips and seal set as well as the subsequent ball dropped to break a shear restraint on the lock sleeve shown before the lock sleeve starts moving uphole under spring force; 100091 FIG, 4 is the view of FTG, 3 with the spring moving a sleeve uphole after picking up to align the locking groove with the dogs that then locks the dogs to a groove in the outer housing with the packer and slips retracted preventing another grip or seal by the test packer; 100101 FIG, 5 is the run in position for the hydraulically driven sleeve variation of the present invention; 1001!] FIG. 6 is the view of FTG, S with the pressure applied on the first ball to unlock the dogs so that the packer can later set with setting down weight; 100121 FIG. 7 is the view of FIG. 6 with the slips and seal set as well as the subsequent ball dropped to break a shear restraint on the lock sleeve shown before the lock sleeve starts moving downhole for the lock position; 100131 FIG. S is the view of FIG. 7 showing the tool picked up and the sleeve moved uphole to lock the dogs that are now in alignment with the locking groove due to picking up.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

100141 Referring to FIG. 1, the packer 10 has a seal assembly 12 and a cone 14 that can wedge under slips 16. The outer housing 18 is run in until it finds support on a liner hanger that is not shown and that is hung off a liner hanger assembly that is also not shown that is set against the casing 20. The mandrel 22 is initially held to the outer housing 18 by dogs 24 extending into groove 26 and locked in that groove with sleeve 28. A series of collet fingers 30 terminate in heads 32 that are initially supported in surface 34 to form a seat for a ball 36 so that applying pressure on the seated ball 36 in FIG. 2 results in surface 38 moving away from dogs 24 so that setting down weight on mandrel 22 will allow for compression of the seal assembly 12 after the slips 16 are ramped out by cone 14. The packer is now set and the pressure integrity of the casing can be tested.

100151 When it is time to unset and lock the packer 10 in the retracted position, the mandrel 22 is picked up to get the groove 26 into axial alignment with dogs 24. A second and larger ball is dropped on heads 32 that have now moved to a second location as the first ball 36 moved them axially to pass through. The pressure builds to break shear pin 40 pushing the heads 32 further down so they can open to r&ease the larger ball that is not shown and shift the sleeve 42. The axial movement of heads 32 lets them open further to let the second and larger ball through. The spring 44 can then push the surface 38 against the dogs 24 when the dogs 24 are in groove 26 as shown in FIG, 4, Now the mandrel 22 is locked against relative movement with respect to the outer housing 18 and the packer 10 cannot set even if landed on a support and weight is set down. Now the completion process can continue in the same trip with completion fluid delivered through mandrel 22 while the work string is rotated and/or reciprocated to facilitate the delivery of completion fluid. A circulating sub that is not shown can be located above the packer 10 and operated th a combination of axial and rotational movement to open a circulation port above the packer 10 for circulation or reverse circulation down to that location.

100161 The embodiment of FIGS. 5-8 works the same way except there is no return spring 44, Instead, surface 46 holds the dogs 24' in the locked position initially in groove 26'. Dropping ball 36' then positions recessed surface 48 opposite dogs 24' and setting down weight will now set the packer 10'. To lock the packer 10' in the released position a second ball is dropped on the collet heads 32' that have already shifted axially to release the first ball 36' and are now supported to take a larger ball for a second movement after breaking the shear member 40' that will result in putting raised surface 50 behind the dogs 24' since picking up before pressuring up a second time allowed the dogs 24' to get axially aligned with groove 26' and the second shifting move in the downhole direction has brought raised surface 50 behind the dogs 24' to trap them in groove 26'. The work string supporting the packer 10' can now be rotated and reciprocated for the subsequent completion operation where completion fluid is then introduced in the same trip.

As before a circulation sub that is not shown can be added above the packer 10' to allow circulation and/or reverse circulation above the packer 10' as needed.

100171 Those skilled in the art will appreciate that no drag blocks are used that could damage the casing when later rotating and/or reciprocating on subsequent completion steps. The lock system is enabled with fluid pressure and is previously disabled after running in with fluid pressure. The ball seat is shiftable to accommodate two ball landings while letting the balls pass to accomplish the initial unlocking or the relocking after the casing pressure integrity test is completed. This then locks the packer so it can be rotated and/or reciprocated to facilitate farther completion operations in the same trip. The use of slips in the packer keeps the load off the liner hanger so the risk of overstressing the liner top at the seal of the liner hanger is avoided.

100181 The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equiva'ent scope of the claims below: