Liner Hanger Running Tool with Contingency Release

This application claims the benefit of the filing date of U.S. provisional application No. 63/651,763 filed on 24 May 2024. The entire disclosure of the prior application is incorporated herein by this reference for all purposes.

This disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in examples described below, more particularly provides a liner hanger running tool.

A liner is a protective lining used in a wellbore. A liner hanger is used to anchor the liner in a previously installed liner or casing.

After the liner hanger has been set in the previous liner or casing, it is normal procedure to release a running tool from the liner hanger, so that the running tool and a work string used to convey the liner into the well can be retrieved from the well. Unfortunately, in some circumstances the running tool fails to release from the set liner hanger. This situation can result in expensive and time-consuming operations to mitigate this problem.

It will, therefore, be appreciated that improvements are continually needed in the art of designing, constructing and operating running tools for use in subterranean wells. The present disclosure provides such improvements, which may be used in a variety of different types of well environments and well configurations.

Representatively illustrated inis a systemfor use with a subterranean well, and an associated method, which can embody principles of this disclosure. However, it should be clearly understood that the systemand method are merely one example of an application of the principles of this disclosure in practice, and a wide variety of other examples are possible. Therefore, the scope of this disclosure is not limited at all to the details of the systemand method described herein and/or depicted in the drawings.

As depicted in, a liner stringis installed in a wellboreand is secured to a previously installed liner or casingwith a liner hanger. A work stringwith a running toolis used to convey the liner stringin the wellbore, and then to set the liner hangerwhen it is appropriately positioned in the previous liner or casing.

In theexample, the liner hangeris set by applying increased pressure in the work string. The applied pressure causes slipsto extend outward from the liner hangerand grip an interior surface of the previous liner or casing. A packer sectionof the liner hangerincludes additional slipsand an annular sealthat extend outwardly to grip the interior surface and seal against the interior surface, respectively, after the initial slipsare set.

After the liner hangeris set, the running toolis released from the liner hanger, so that the running tool and the remainder of the work stringcan be retrieved from the well. The work stringmay be manipulated at the surface of the well in order to release the running toolfrom the liner hanger. For example, the work stringmay be rotated in a clockwise (right-hand as viewed from above) or counter-clockwise (left-hand as viewed from above) rotational direction using a rotary table, tong, iron roughneck or other torque applying apparatus, and the work string may be picked up (raised) or slacked-off (lowered) at the surface using a draw works, top drive or other lifting apparatus. The running toolin this example includes features that allow the running tool to be released from the liner hanger, even if an initial attempt to release the running tool is unsuccessful.

Referring additionally now to& B cross-sectional views of examples of the liner hangerand the running toolare representatively illustrated. The liner hangerand the running toolare described below as they may be used in thesystemand method, but the liner hanger and running tool may be used in other systems and methods in keeping with the scope of this disclosure.

An internally threaded upper connectorof the running toolincludes torque locksto allow torque to be applied from the work stringto the running tool and liner hangerin both clockwise and counter-clockwise rotational directions. The upper connectoris formed at an upper end of a generally tubular mandrelof the running tool.

Torque applied to the mandrelis transmitted to an outer housingvia screws(only one of which is visible in). In this example, the outer housingincludes two sectionsjoined by castellations. An upper end of the liner hangeris connected to the lower outer housing sectionwith additional castellations.

An externally threaded float nutis used to secure the liner hangerto the running tool. The float nutis disposed on axially extending keys(only one of which is visible in& B) that are secured on the mandrel. The keys are received in axially extending slots formed in the float nut. The keysare constrained to rotate with the mandrel, so rotation of the mandrel also causes rotation of the float nut.

The float nutis left-hand threaded into the upper end of the liner hanger. Thus, right-hand (clockwise as viewed from above) rotation of the mandrelrelative to the liner hangerwill cause the float nutto unthread from the liner hanger.

In a procedure described more fully below for releasing the running toolfrom the liner hanger, the work stringis slacked off, thereby applying a compressive load to the running tool, before rotating the work string and mandrel. A bearingis provided in the running toolto mitigate any excessive friction due to the compressive load.

A coil springapplies a downwardly biasing force to a torque lockengaged with the keysand the outer housing. As described more fully below, the torque lockmust be disengaged from the keysto permit the mandrelto rotate relative to the outer housingand the liner hanger. The torque lockis disengaged by applying the compressive load to the running tool, with the compressive load being sufficient to overcome the biasing force exerted by the coil spring.

However, the mandrelis prevented from displacing downward relative to the outer housingto compress the springby dogs(only one of which is visible in) engaged in a circumferentially extending slotformed on the mandrel. The dogsextend radially through an upper end of the outer housing upper section

The dogsare radially inwardly supported in engagement with the slotby a release sleevesurrounding the mandrel. An annular pistonis secured in the release sleeve.

Portsformed through the mandrelpermit pressure applied to the interior of the work stringand the mandrel to be communicated to an annular chamber between the mandrel and the annular piston. When sufficient pressure is applied to the interior of the mandrel, the release sleevewill displace upward, to thereby permit the dogsto displace radially outward and out of engagement with the slot.

Shear screwsextend through the outer housing upper sectionand into axially extending slots(only one of which is visible in) formed on the mandrel. When the shear screwsare in the axial slots, they releasably secure the mandrelagainst rotation relative to the outer housing. However, when the mandrelis displaced downward relative to the outer housingby the compressive load due to slacking off on the work stringat the surface, the shear screwsare received in a circumferentially extending slotformed on the mandrel, and the shear screwsat that point will not resist rotation of the mandrel relative to the outer housing.

Shear screwsextend through the outer housing upper sectionand into axially extending slots(only one of which is visible in) formed on the mandrel. When the shear screwsare aligned with the axially extending slotsas depicted in, the shear screws do not impede downward displacement of the mandrelrelative to the outer housing. However, if the mandrelis rotated counter-clockwise relative to the outer housing, as described more fully below, the shear screws will no longer be aligned with the axial slotsand will releasably prevent downward displacement of the mandrel relative to the outer housing.

Referring additionally now to, a partially cross-sectional view of an example of the running toolin a run-in configuration is representatively illustrated. Therunning toolmay be used with the liner hanger, or it may be used with other liner hangers. Therunning toolis similar in most respects to the& B running tool, so the same reference numbers are used into indicate components similar to those described above.

One difference in theexample is that additional shear screwsare used. Another difference is that a snap ringis carried in an upper end of the release sleevefor engagement with a grooveformed on the mandrelbelow the upper connectorwhen the release sleeve is displaced upward. In other examples, the snap ringcould instead be carried on the mandreland the groovecould be formed in the release sleeve.

Init may be seen that the shear screwsare received in a circumferentially extending slotformed on the mandrel, as well as in the axially extending slot. Thus, in the run-in configuration of the running tool, the shear screwsdo not prevent axial displacement or rotation of the mandrelrelative to the outer housing. However, it will be appreciated that, if the mandrelis rotated appropriately relative to the outer housing, the shear screwswill no longer be aligned with the axial slots, at which point the shear screws will releasably prevent downward displacement of the mandrel relative to the outer housing.

Another shear screwreleasably secures the release sleeveto the annular piston. The pistonis threaded onto the inner mandrel.

Referring additionally now to, a cross-sectional view of the running tool, taken along lineA-A ofis representatively illustrated. In this view, a configuration of the torque lockand its interaction with the keysand the outer housingcan be more clearly seen.

In this example, the torque lockis secured in the lower outer housing sectionwith the torque screws. The keysare received in circumferentially extending slotsformed in the torque lock, and in axially extending slotsformed in the mandrel.

The circumferential slotspermit only limited rotation of the mandreland keysrelative to the outer housing. Specifically, the circumferential slotspermit only limited counter-clockwise (left-hand) rotation of the mandreland keysrelative to the outer housing. When the mandreland keysare rotated counter-clockwise relative to the outer housingto the extent permitted by the slots, as described more fully below, the shear screwswill not be aligned with the axial slots, and so the shear screws will resist downward displacement of the mandrel relative to the outer housing.

Referring additionally now to, a partially cross-sectional view of the running toolin a partially released configuration is representatively illustrated. In this view, sufficient fluid pressure has been applied to the interior of the work stringand mandrelto shear the shear screwsand displace the release sleeveupward. The snap ringcan now engage the grooveto maintain the release sleevein this position.

The release sleeveno longer retains the dogsin engagement with the circumferential slotson the mandrel. Thus, the mandrelcan now be displaced downward relative to the outer housing.

Referring additionally now to, a partially cross-sectional view of the running toolin a released configuration is representatively illustrated. In this view, a compressive load has been applied to the running toolby slacking off on the work stringat the surface. The compressive load is sufficient to compress the springand displace the mandreldownward relative to the outer housing.

The downward displacement of the mandrelrelative to the outer housinghas caused the keysto disengage from the circumferential slotsof the torque lock. This disengagement allows the mandrelto be rotated relative to the outer housing.

Note that the shear screwsare no longer received in the axial slots, but are instead received in the circumferential sloton the mandrel. Thus, the shear screwsdo not impede rotation of the mandrelrelative to the outer housing.

Similarly, the shear screwshave displaced through the axial slotsand are now received in another circumferentially extending slotformed on the mandrel. Thus, the shear screwsalso do not impede rotation of the mandrelrelative to the outer housing.

The mandrelis rotated in a clockwise direction relative to the outer housingby rotating the work stringat the surface (in a right-hand direction as viewed from above). The outer housingdoes not rotate with the mandrel, due to the engagement of the outer housing with the liner hanger(see, castellations).

The clockwise rotation of the mandrelhas caused the float nutto unthread from the liner hanger. Note that, in, the float nutis displaced upward relative to the mandrel. Thus, the running toolis now released from the liner hangerand can be retrieved to the surface with the remainder of the work string.

Referring additionally now to, a partially cross-sectional view of the running toolin a configuration in which a contingency release procedure is initiated is representatively illustrated. The contingency release procedure is performed if the release procedure described above and depicted inis unsuccessful (for example, if the release sleevedid not displace upward relative to the mandrelupon application of pressure to the interior of the work string).

If a compressive load or force has been applied to the running tool(e.g., by slacking off on the work stringat the surface) in the initial release procedure, then preferably the compressive load is removed, for example, by picking up on the work string. However, note that it is not necessary to remove any compressive load or force on the running toolprior to commencing the contingency release procedure.

In theexample, the release sleevehas not been displaced upward relative to the mandrel. Therefore, the dogsare still supported in engagement with the circumferential slots, and so the mandrelcannot be displaced downward relative to the outer housingto compress the springand disengage the torque lockfrom the keysto permit rotation of the mandrel relative to the outer housing.

Referring additionally now to, a partially cross-sectional view of the running toolin a partially released configuration is representatively illustrated. In this view, the mandrelhas been rotated in a left-hand direction relative to the outer housingby rotating the work stringin a counter-clockwise direction (as viewed from above) at the surface.

Limited counter-clockwise rotation of the mandrelrelative to the outer housingis permitted by the circumferential slotsin the torque lock(see). The shear screwsresist such rotation, but the shear screws will shear when sufficient torque is applied to the work string. Note that the shear screwsare sheared as depicted in.

Note also that the dogsare now rotationally aligned with axially extending slotsformed on the mandrel. Thus, the mandrelcan now be displaced downward relative to the outer housing, even though the release sleevestill prevents radially outward displacement of the dogs.

Due to the counter-clockwise rotation of the mandrelrelative to the outer housing, the shear screwsare no longer axially aligned with the axial slotson the mandrel (see). Instead, the shear screwsare now rotationally aligned with circumferentially extending shouldersformed on the mandrel. Thus, in order to displace the mandreldownward relative to the outer housing, a sufficient compressive load will need to be applied to the mandrelto shear the shear screwsand compress the spring.

Referring additionally now to, a partially cross-sectional view of the running toolin a released configuration is representatively illustrated. In this view the mandrelhas displaced downward relative to the outer housingby slacking off on the work stringat the surface. In this manner, sufficient compressive load has been applied to the running toolshear the shear screwsand compress the spring.

The torque lockis now disengaged from the keys, thereby allowing the mandrelto be rotated relative to the outer housing. The mandrelhas been rotated in a right-hand direction by rotating the work stringin a clockwise direction at the surface.

The float nuthas unthreaded from the liner hanger, thereby releasing the running toolfrom the liner hanger. The running tooland the remainder of the work stringcan now be retrieved from the well.

Note that, in each of the hydraulic release () and contingency release () procedures, as the float nutunthreads from the liner hanger, an externally threaded torque nutwill rotate and displace downwards until it shoulders inside the outer housing lower section. When this occurs, the torque path changes and the work stringand liner stringwill rotate together.

Note that, in each of the hydraulic release and contingency release procedures, the mandrelcould be configured or machined so that it does not include the axially extending slots. In that case, the second shear upon “slack off” (shearing of the shear screws) will give an operator at the surface a positive indication that the running toolhas been placed in compression, regardless of the release mode (hydraulic release or contingency release).

It may now be fully appreciated that the above disclosure provides significant advancements to the art of designing, constructing and operating liner hanger running tools for use in subterranean wells. In one example described above, if release of the running toolfrom the liner hangeris initially unsuccessful, the mandrelcan be rotated counter-clockwise somewhat relative to the outer housing(causing the shear screwsto shear) to thereby enable the mandrel to be displaced downward relative to the outer housing. Shearing of the shear screws(due to the downward displacement of the mandrel) will provide an indication to an operator at the surface that the contingency release procedure has been successfully initiated. The mandrelcan then be rotated clockwise relative to the outer housingto unthread the float nutfrom the liner hanger.

The above disclosure provides to the art a method of releasing a work stringincluding a running toolfrom a liner hangerin a subterranean well. In one example, the method can comprise: rotating the work stringin a first rotational direction; then slacking off on the work string, thereby applying a compressive force to the running tool; and then rotating the work stringin a second rotational direction opposite to the first rotational direction, thereby releasing the running toolfrom the liner hanger.