Lock Ring Actuator for Tubing Hanger Installation

A hanger assembly includes: a main body; a lock ring coupled to the main body and configured to expand radially outward into a profile on an inner diameter of the wellhead; and an actuator, wherein the actuator is capable of transferring an axial force from the actuator into outward radial expansion of the lock ring toward the profile on the inner diameter of the wellhead. An interface between the actuator and the lock ring is shaped such that: axially downward movement of the actuator from a starting position to an intermediate position actuates the lock ring into the profile; and axially downward movement of the actuator from the intermediate position to a pre-load position applies a pre-load to the hanger assembly.

BACKGROUND

Conventional wellhead systems include a wellhead housing and a subsurface casing string extending from the wellhead into the well bore. During a drilling procedure, a drilling riser and BOP are installed above a wellhead housing (casing head) to provide pressure control as casing is installed, with each casing string having a casing hanger on its upper end for landing on a shoulder within the wellhead housing. Successive casing hangers carrying casing strings of decreasing diameter are installed through the wellbore, and then, a tubing string is installed through the well bore. A tubing hanger connectable to the upper end of the tubing string is supported within the wellhead housing above the last casing hanger, which carries the smallest diameter casing string, for suspending the tubing string within the casing string. Upon completion of this process, the BOP is replaced by a Christmas tree installed above the wellhead housing, with the tree having a valve to enable the oil or gas to be produced and directed into flow lines for transportation to a desired facility.

For various reasons, a tubing hanger or casing hanger within the wellhead may move axially upward, particularly when the wellhead is part of a production system where downhole fluids at elevated temperatures thermally expand the casing string and thus exert a substantial upward force on the casing hanger. Since the casing hanger seal is intended for sealing at a particular location on the wellhead, upward movement of the casing hanger and the seal assembly is detrimental to reliably sealing the casing annulus. Further, for various reasons, the casing hanger may stack higher than intended. Thus, it must be ensured that the tubing hanger is properly sized to lock to the wellhead and that the casing hanger is prevented from moving axially in response to such axial forces.

Various tubing hanger designs and methods have been conceived of for ensuring the tubing hanger is locked to the wellhead housing and the tubing hanger system and casing hanger are rigidized (locked axially) within the wellhead housing. A tubing hanger, once run in and locked into the wellhead, is intended to prevent axial movement of the uppermost casing hanger and seal assembly with respect to the wellhead. Typically, a tubing hanger is run into the wellhead, landed on the casing hanger, and locked to a locking profile on an inner wall of the wellhead housing, which also acts to secure the casing hanger within the wellhead. To install existing tubing hangers, it is first necessary to run a lead impression tool into the wellhead to measure the distance between the top of the casing hanger and the housing locking profile. The lead impression tool is a small block of soft metal, usually lead, which is lowered into the wellhead to take an impression to determine the internal profile of the wellhead, which after being retrieved can be measured to determine the distance between the top of the casing hanger and the housing locking profile. With this information, the tubing hanger can be adjusted at the surface so that once the tubing hanger is run in and secured to the wellhead, it provides a zero-gap connection between the tubing hanger, the casing hanger, and the wellhead housing and creates any desired pre-load.

This process of taking measurements in the wellhead via a lead impression tool, retrieving the tool to the surface, and then adjusting and installing a tubing hanger into the wellhead is a time-consuming installation process requiring multiple trips into the wellhead. It is now recognized that a need exists for a tubing hanger system that allows for a single-trip installation process.

DETAILED DESCRIPTION

Certain embodiments of the present disclosure may be directed to a tubing hanger system that may be installed within a wellhead system in a single trip. The tubing hanger system may include multiple pieces that are coupled together such that the tubing hanger may be locked to an inner wall of a high-pressure wellhead housing while applying a preload on a casing hanger, thereby rigidizing the tubing hanger system and casing hanger within the wellhead housing. The tubing hanger system may be run into the wellhead system until the tubing hanger system abuts the casing hanger. Then, the tubing hanger system may be picked up until the tubing hanger system is locked against an inner wall of the high-pressure housing. Lastly, a space-out mechanism of the tubing hanger system may actuate such that it takes up any gaps formed axially by being picked up, thus rigidizing the tubing hanger system and casing hanger within the wellhead housing. The installation process for the tubing hanger system may be accomplished entirely during a single trip into the wellhead as opposed to a first trip with a lead impression tool followed by an adjustment of the tubing hanger system at the surface and a subsequent trip downhole to install the adjusted tubing hanger system. The disclosed systems and method provide both time savings (since only one trip into the wellhead is necessary) and cost savings (since an additional lead impression tool is not required) compared to existing tubing hanger installation techniques.

Certain embodiments of the present disclosure may also be directed to a seal assembly having enhanced rigidity. The seal assembly may be configured such that fluid may apply pressure to the inner diameter of the seal assembly's lower body, thereby pushing the lower body down. When the lower body is pushed down, a pressure-actuated release mechanism (such as a shear pin) may be actuated (e.g., broken), allowing the lower body to descend further while a ramp ring and spring reduce the size of any existing gap between the casing hanger and wellhead. Such embodiments allow for enhanced rigidization of the wellhead system with minimal cost.

Referring now toFIGS.1A-3B, certain components of a wellhead system1are illustrated according to one or more embodiments of the present disclosure. The illustrated wellhead system1may be a subsea wellhead assembly. However, similar techniques may be used in land-based wellhead systems as well. The wellhead system1may include a wellhead housing2, a casing hanger10, a tubing hanger system20, and a locking mechanism60. The casing hanger10may be landed within the wellhead housing2. The tubing hanger system20may then be landed upon the casing hanger10within the wellhead housing2. Lastly, the locking mechanism60may be landed upon the tubing hanger system20within the wellhead housing2. The wellhead housing2may include a central bore3having locking profile4disposed thereon. The locking mechanism60may engage the locking profile4of the wellhead housing2in order to lock the casing hanger10, the tubing hanger system20, and the locking mechanism60in place within the wellhead housing2and rigidize the system.

The casing hanger10may include a casing hanger body11having an upper load shoulder12and a radially interior profile13. The upper load shoulder12may be tapered inwards towards the interior profile13and ridges may be formed along the upper load shoulder12. However, one of ordinary skill in the art would understand that in other embodiments, the upper load shoulder may be tapered outwards away from the interior profile or may not be tapered at all. Additionally, one of ordinary skill in the art would understand that in other embodiments, the upper load shoulder may be smooth or curved instead of having ridges.

The tubing hanger system20may include a tubing hanger body30and a space-out mechanism100. In one or more embodiments, the space-out mechanism may include a ramp ring40and a piston50. However, one of ordinary skill would understand that space-out mechanisms of other embodiments may include a plurality of ramp rings or wedges. The tubing hanger body30, the ramp ring40, and the piston50may be assembled together before being inserted into the wellhead housing2such that the tubing hanger system20may be installed in a single trip. The manner in which each of the parts in the tubing hanger system20are coupled will be discussed further below. Additionally, the tubing hanger system20may be run into the wellhead housing2and disposed such that the tubing hanger body30seals against the interior profile13of the casing hanger body11and the piston50abuts the upper load shoulder12of the casing hanger10. In one or more embodiments, to ensure that tubing hanger system20is properly seated on the casing hanger10, one or more safety lock mechanisms may be used. The safety lock mechanisms according to one or more embodiments of the present disclosure will be discussed further below.

Still referring toFIGS.1A-3B, the tubing hanger body30, according to one or more embodiments of the present disclosure, may include a radially exterior profile31defined, in part, by a first sealing profile32, a second sealing profile33, an upward facing contact surface34, a downward facing contact surface35, and an axially extending pin slot36. The first sealing profile32may include a first seal groove32ain which a tubing hanger to casing hanger seal37is disposed, a second seal groove32bin which an o-ring may be disposed, a third groove32cin which a retainer ring21may be disposed, and a fourth seal groove32din which a first tubing hanger to piston seal38may be disposed. The second sealing profile33may include groove33ain which a second tubing hanger to piston seal39may be disposed.

Further, the ramp ring40of the space-out mechanism100, according to one or more embodiments of the present disclosure, may include an upper contact surface41, ramp surfaces42, and rotational stop surfaces43. The ramp ring40may be disposed adjacent to the tubing hanger body30such that the ramp ring40is positioned about the second sealing surface33of the tubing hanger body30and, at least when the tubing hanger system20is run-in and when the tubing hanger system20is in a fully locked position, the upper contact surface41may contact the downward facing contact surface35of the tubing hanger body30. Additionally, in one or more embodiments, a bottom of the ramp ring40may have a plurality of ramp surfaces42and a plurality of rotational stop surfaces43. By way of example, in one or more embodiments, the ramp ring40may include three ramp surfaces each extending 120° circumferentially about the ramp ring40. However, one of ordinary skill in the art will understand that in other embodiments, the ramp ring may have a single ramp surface and a single rotational stop surface or any combination of equal numbers of ramp surfaces and rotational stop surfaces that match the number of ramp surfaces and rotational stop surfaces of the piston. Further, in one or more embodiments of the present disclosure, the ramp surfaces42may have a constant 3.5° taper. However, one of ordinary skill in the art will understand that in other embodiments the ramp surface may include steps or ridges and/or may have a constant or changing taper in the range of 0.5°-7°. Alternatively, the ramp surface may include any range of angles, surface geometries, and/or coatings that prevent rotation once installed.

Additionally, the piston50of the space-out mechanism100may include a lower load shoulder51, a first interior seal surface52, a second interior seal surface53, an interior shoulder54, ramp surfaces55, rotational stop surfaces56, and a threaded pin borehole57. The piston50may be disposed adjacent to the casing hanger10, the tubing hanger body30, and the ramp ring40such that piston is positioned about the first sealing surface32and the second sealing surface33of the tubing hanger body30. Further, the piston50may abut the casing hanger20on one side and the ramp ring40on the other side. Thus, in one or more embodiments, the lower load shoulder51may abut the upper load shoulder12of the casing hanger10. As such, the lower load shoulder51may be tapered to match the taper of the upper load shoulder12of the casing hanger10and ridges may be formed along the lower load shoulder51to match the ridges of the upper load shoulder12of the casing hanger10. However, as discussed above with regard to the upper load shoulder12of the casing hanger10, one of ordinary skill in the art would understand that in other embodiments, the lower load shoulder may be tapered in a number of ways as long as the taper of the lower load shoulder matches the taper of the upper load shoulder. Additionally, one of ordinary skill in the art would understand that in other embodiments, the upper load shoulder may be smooth or curved instead of having ridges.

Further, the first interior seal surface52and second interior seal surface53of the piston50may be disposed such that when the tubing hanger system20is fully assembled, the first tubing hanger to piston seal38and the second tubing hanger to piston seal39may seal against the first interior seal surface52and the second interior seal surface53of the piston50, respectively. Furthermore, when the tubing hanger system20is disposed within the wellhead housing2and landed on the casing hanger10, the first sealing profile32of the tubing hanger body30may sit within the casing hanger10such that the tubing hanger to casing hanger seal37seals against the interior profile13of the casing hanger10. This sealing profile created between the casing hanger10, the tubing hanger body30, and the piston50may create a piston force that acts in a downward direction against the interior shoulder54of the piston50, which may hold the piston50in abutment with the casing hanger10in the event that the tubing hanger body30is shifted in an upward direction. Additionally, in one or more embodiments, the threaded pin borehole57of the piston50may be aligned with the pin slot36of the tubing hanger body30, and an anti-rotation pin24may be coupled to the threaded pin borehole57such that the anti-rotation pin24rests within the pin slot36. This anti-rotation pin, according to one or more embodiments of the present disclosure, may rotationally couple the piston to the tubing hanger body30such that the ramp ring40may rotate relative to the piston50while allowing the tubing hanger body30to move axially relative to the piston50so that any gap that is formed in locking the tubing hanger system20and casing hanger10to the wellhead housing2may be filled. However, one of ordinary skill in the art would understand that in other embodiments a variety of methods may be used to rotationally secure the piston and the tubing hanger body such that the ramp ring may rotate relative to the tubing hanger body without also rotating the piston.

Furthermore, still referring toFIGS.1A-3B, the ramp surfaces55of the piston50may be configured to abut the ramp surfaces42of the ramp ring40at least when the tubing hanger system20is run-in and when the tubing hanger system20is in a fully locked position. As discussed above with regard to the ramp surfaces42of the ramp ring40, the ramp surfaces55of the piston50may be designed in various ways so long as the ramp surfaces55match the ramp surfaces42. By way of example, in one or more embodiments, the piston may include three ramp surfaces each extending 120° circumferentially about the piston50. However, one of ordinary skill in the art will understand that in other embodiments, the piston may have a single ramp surface and a single rotational stop surface or any combination of equal numbers of ramp surfaces and rotational stop surfaces that match the number of ramp surfaces and rotational stop surfaces of the ramp ring. Further, in one or more embodiments of the present disclosure, the ramp surfaces55may have a constant 3.5° taper. However, one of ordinary skill in the art will understand that in other embodiments the ramp surface may include steps or ridges and/or may have a constant or changing taper in the range of 0.5°-7°. One of ordinary skill will appreciate that the ramp surfaces are designed such that the contact between the ramp surfaces is self-locking and compressive forces between the surfaces will not cause the piston and ramp ring to rotate relative to each other once the tubing hanger system is in the fully locked position. Further, the rotational stop surfaces56of the piston50and the rotational stop surfaces43of the ramp ring40may be configured to abut each other at least when the tubing hanger system20is run in and may prevent the piston and ramp ring from rotating relative to each other in one direction.

Additionally, the locking mechanism60, according to one or more embodiments of the present disclosure, may include a locking mandrel61and locking dogs62. The plurality of locking dogs62may be supported around the locking mandrel61. The locking mechanism60may be run into the wellhead housing2until the locking mechanism60abuts the upward facing contact surface34of the tubing hanger body30. In one or more embodiments, a bottom surface of the locking dogs62may directly abut the upward facing contact surface34and may be pushed outward into the locking profile4of the wellhead housing2by a compressive force caused by the locking mandrel61pushing down on the locking dogs62. The locking dogs62may have ridges disposed on an outer surface that match the locking profile4disposed along the central bore3of the wellhead housing2.

Further, the tubing hanger system20may include one or more safety locks to ensure that the system is properly run into the wellhead housing2and features of the system are not activated prematurely. By way of example, in one or more embodiments, a retainer ring21may be included in the tubing hanger system20so as to make sure that the piston50is properly seated upon the casing hanger10and the seals of the tubing hanger body30are set within the piston50and the casing hanger10as necessary for the system to function properly. The retainer ring21may be a split ring disposed within the third groove32cof the tubing hanger body30and may have an uncollapsed outer diameter that is greater than both the diameter of the interior profile13of the casing housing10and the first interior seal surface52of the piston50. Further, in a pre-run-in assembled state, the third groove32cand the retainer ring21may be disposed below the lower load shoulder51of the piston50. This disposition of the retainer ring21and third groove32cmay be such that the lower load shoulder51of the piston50cannot abut the upper load shoulder12of the casing hanger10until the retainer ring21is collapsed into the third groove32c. The retainer ring21may include an upper contact surface22and a lower contact surface23. The lower contact surface23may be tapered such that downward forces from the piston50and/or tubing hanger body30during run-in push the tapered lower contact surface23into an interior edge of the upper load shoulder12of the casing hanger10and cause the retainer ring21to collapse into the third groove32c. Once collapsed, the outer diameter of the retainer ring21may be smaller than the interior profile13of the casing hanger10, allowing the tubing hanger system20to properly seat within and against the casing hanger10. Thus, in one or more embodiments, the retainer ring21needs to be collapsed in order for the lower load shoulder51of the piston50to be able to abut the upper load shoulder12of the casing hanger10. Additionally, various other safety locks may be used in one or more embodiments of the present disclosure.

Referring now toFIG.4, another safety mechanism according to one or more embodiments of the present disclosure is illustrated. A spring loaded pin disposed within the ramp ring40may be installed during assembly of the tubing hanger system20and engage the tubing hanger body30so as to rotationally lock the ramp ring to the tubing hanger body until the proper time in the tubing hanger system run-in in which the ramp ring must be rotationally actuated in order to take up any axial space created by the installation procedure.

The safety mechanism of the tubing hanger system20may include a safety lock pin70, a safety lock spring71, and a safety lock rod72. The safety lock pin70and the safety lock spring71may be disposed within the ramp ring40, and the safety lock rod72may be disposed within the tubing hanger body30. The ramp ring40, in one or more embodiments, may include a pin blind hole44disposed in an upper contact surface41and a pin securing mechanism45. The safety lock spring71may be disposed within the pin blind hole44abutting a bottom of the blind hole, and the safety lock70pin may be disposed above the safety lock spring71in the blind hole such that the safety lock pin70is pushed up towards the tubing hanger body30. The safety lock pin70may include a safety lock pin body70aand a safety lock pin flange70b, in which the diameter of the safety lock pin flange70bis greater than the diameter of the safety lock pin body70a. The pin securing mechanism45may be disposed in the opening of the pin blind hole44and may have an inner diameter larger than the safety lock pin body70abut smaller than the diameter of the safety lock pin flange70bsuch that the safety lock pin70is maintained within the pin blind hole44while the safety lock pin body70ais able to extend past the upper contact surface41of the ramp ring40.

Additionally, the tubing hanger body30, in one or more embodiments, may include an elongated hole58that extends from an upward facing contact surface34to a downward facing contact surface35. Further, a pin counterbore59may be sunk into the downward facing contact surface35and concentric with the hole58. An inner diameter of the pin counterbore59may be slightly larger than the outer diameter of the safety lock pin body70a, and the pin counterbore59may be configured to receive the safety lock pin70when the tubing hanger system20is assembled before run-in. Further, the safety lock rod72may be disposed within the hole58. The safety lock rod72may be longer than the length of the hole58and the pin counterbore59such that when the safety lock pin70extends into the pin counterbore59, the top end72aof the safety lock rod72extends above the upward facing contact surface34and when the safety lock rod72is compressed down to the upward facing contact surface34into the hole58, the bottom end72bof the safety lock rod72is even with or extends slightly below the downward facing contact surface35.

Further referring toFIG.4, in one or more embodiments of the present disclosure, when the tubing hanger system20is assembled before run-in, the safety lock pin70may engage the pin counterbore59. During the installation of the tubing hanger system20within a wellhead housing, installation of a locking mechanism may cause a locking mandrel to compress the safety lock rod72into the hole58, which will cause the bottom end72bof the safety lock rod72to push the safety lock pin70out of the pin counterbore59. Once the safety lock pin70is removed from the pin counterbore59, the tubing hanger body30and the ramp ring40will no longer be rotationally locked with respect to each other allowing the ramp ring40to rotate relative to the piston50along their respective ramp surfaces in order to remove any axial gaps in the tubing hanger system20created during the process of locking the tubing hanger system within the wellhead housing.

Referring now toFIGS.5A and5B, a tubing hanger system520, according to one or more embodiments of the present disclosure, is illustrated. As discussed previously, the tubing hanger system520may include a tubing hanger body530and a space-out mechanism500. Further, the space-out mechanism500may include a ramp ring540and a piston550. Additionally, in one or more embodiments, the ramp ring540of the space-out mechanism500may be rotationally coupled to the tubing hanger body530by a circumferential spring mechanism580. The circumferential spring mechanism580may be coupled to the ramp ring540on a first end and to the tubing hanger body530on a second end. The circumferential spring mechanism580may include a spring581, spring connectors582, a transfer block583, and bolts584. The spring581may be disposed within a circumferential groove531located on the second sealing profile533of the tubing hanger body530. The circumferential groove531may be disposed between the downward facing contact surface (not shown) of the tubing hanger body530and the fourth seal groove (not shown), which is disposed on the second sealing profile533of the tubing hanger body530. Further, the spring581may be directly coupled to the tubing hanger body530by a spring connector582on a first end of the circumferential groove531and may be directly coupled to the transfer block583by a spring connector582within a distal portion of the circumferential groove531. The transfer block583may be directly coupled to the ramp ring540by bolts584.

In one or more embodiments, when assembling the tubing hanger system520before run-in, the circumferential spring mechanism580may be preloaded such that when a safety mechanism rotationally locking the tubing hanger body530and the ramp ring540is disengaged, the space-out mechanism500self-actuates to rotate the ramp ring540against the piston550to extend the space-out mechanism500axially and remove any axial gaps that have formed during installation of the tubing hanger system520into wellhead housing. When the space-out mechanism500is actuated, the rotation of the ramp ring will cause the ramp surface of the ramp ring540to bear against and rotate against the ramp surface of the piston530and extend the space-out mechanism500axially.

By way of example, in one or more embodiments, the space-out mechanism500may be configured such that the preload puts the spring581in tension and releasing the safety mechanism causes the spring581to pull the ramp ring540causing it to rotate against the piston550. However, one of ordinary skill would appreciate that in other embodiments, the spring581may be preloaded in compression such that releasing the safety mechanism causes the spring to push the ramp ring540causing it to rotate against the piston550. Additionally, while a single preloaded spring581is illustrated inFIGS.5A and5B, one of ordinary skill would appreciate that in other embodiments, there may be multiple springs situated in series or in parallel and preloaded in tension, compression, or torsion so as to rotate a ramp surface of the ramp ring540against a ramp surface of the piston550causing the space-out mechanism to extend axially and fill in any axial gaps created while rigidizing the tubing hanger system and casing hanger within the wellhead housing.

Referring now toFIGS.6A and6B, a tubing hanger system620, according to one or more embodiments of the present disclosure, is illustrated. As discussed previously, the tubing hanger system620may include a tubing hanger body630and a space-out mechanism600. Further, the space-out mechanism600may include a ramp ring640and a piston650. Additionally, in one or more embodiments, the space-out mechanism may include a ratchet mechanism680disposed inside the tubing hanger system620that is configured to allow a user to remotely rotate the ramp ring640as necessary during run-in and the process of rigidizing the tubing hanger system620within the wellhead housing. The ramp ring640may include a plurality of inclined grooves641disposed circumferentially along its inner diameter. The ratchet mechanism680may be configured to engage the grooves641of the ramp ring640such that each stroke of the ratchet mechanism rotates the ramp ring640by the radial distance of a single groove. The ratchet mechanism680, according to one or more embodiments of the present disclosure, may be a short stroke piston with a ratchet. The ratchet mechanism680may include a piston681, a spring682, an actuation arm683, and a lever684. The piston681and the spring682may be coaxially disposed with one end of the actuation arm683coupled to one end of the piston681. Further, the other end of the actuation arm may be coupled to the lever684, which is itself pinned to a non-moving portion of the piston681, in order to force the lever684to rotate about the pinned connection. The piston681may be remotely controlled by a user so as to actuate the ratchet mechanism680by pulling the actuation arm683such that the lever684rotates out of the groove it is sitting in and then allowing the lever684to rotate back against the edge of a groove under the force of the spring682, which causes the actuation arm to return the lever to its resting position, such that the lever684now engages an adjacent groove; thus, rotating the ramp ring640, accordingly. Further, as discussed above, rotating the ramp ring640causes the ramp ring640to shift against the piston650to extend the space-out mechanism600axially and remove any axial gaps that have formed during installation of the tubing hanger system620into the wellhead housing. When the space-out mechanism600is actuated, the rotation of the ramp ring will cause the ramp surface of the ramp ring640to bear against and rotate against the ramp surface of the piston630and extend the space-out mechanism600axially.

Referring now toFIG.7, a ramp ring rotating mechanism780, according to one or more embodiments of the present disclosure, is illustrated. A space-out mechanism may include the ramp ring rotating mechanism780coupled to a ramp ring. The ramp ring rotating mechanism780may include a piston781and a curved piston rod782. In one or more embodiments, the curved piston rod782may be 3-D printed. Further, the curved piston rod782may be disposed within the piston781and extend from the piston781. An end of the curved piston rod782may be coupled to the ramp ring, and actuating the piston781may cause the curved piston rod782to extend, thus causing the ramp ring to rotate relative to a tubing hanger body and a piston750of a tubing hanger system. Further, as discussed above, rotating the ramp ring may cause the ramp ring to shift against the piston750to extend the space-out mechanism axially and remove any axial gaps that have formed during installation of the tubing hanger system into a wellhead housing. When the space-out mechanism is actuated, the rotation of the ramp ring may cause the ramp surface of the ramp ring to bear against and rotate against the ramp surface of the piston750and extend the space-out mechanism axially.

Referring now toFIGS.8A and8B, a ramp ring rotating mechanism880, according to one or more embodiments of the present disclosure, is illustrated. A space-out mechanism800may include the ramp ring rotating mechanism880coupled to a ramp ring840. The ramp ring rotating mechanism880may include a piston881, an arm882, and a slider883. In one or more embodiments, the arm882may be coupled to the piston881and may be rotated by way of actuation of the piston881, which may be operated remotely by a user. An end of the arm882may be coupled to a first end of the slider883, and a second end of the slider883may be coupled to the ramp ring840. In one or more embodiments, the slider883may be coupled to the arm882and the ramp ring840by pins. Further, actuating the piston881may cause the arm882to rotate, thus causing the slider883to rotate about the pinned connection to the arm882and rotating the ramp ring840relative to a tubing hanger body and a piston850of a tubing hanger system. Further, as discussed above, rotating the ramp ring840may cause the ramp ring840to shift against the piston850to extend the space-out mechanism800axially and remove any axial gaps that have formed during installation of the tubing hanger system into a wellhead housing. When the space-out mechanism800is actuated, the rotation of the ramp ring840may cause the ramp surface of the ramp ring840to bear against and rotate against the ramp surface of the piston850and extend the space-out mechanism800axially.

Referring now toFIGS.9A and9B, a ramp ring rotating mechanism980, according to one or more embodiments of the present disclosure, is illustrated. A space-out mechanism900may include the ramp ring rotating mechanism980coupled to a ramp ring940. The ramp ring rotating mechanism980may be a geared mechanism and may include a curved rack981and a pinion982. In one or more embodiments, the curved rack981may be coupled to a ramp ring940and the pinion982. Further, rotation of the pinion982may cause rotation of the ramp ring940by way of the curved rack981, and the pinion982may be rotated by remote operation by a user. Therefore, in one or more embodiments, rotation of the pinion982may cause the ramp ring940to rotate relative to a tubing hanger body and a piston950of a tubing hanger system. Further, as discussed above, rotating the ramp ring940may cause the ramp ring940to shift against the piston950to extend the space-out mechanism900axially and remove any axial gaps that have formed during installation of the tubing hanger system into a wellhead housing. When the space-out mechanism900is actuated, the rotation of the ramp ring940may cause the ramp surface of the ramp ring940to bear against and rotate against the ramp surface of the piston950and extend the space-out mechanism900axially.

Referring now toFIG.10, a partial cutaway view of a tubing hanger system1020, according to one or more embodiments of the present disclosure, is illustrated. The tubing hanger system1020may include a tubing hanger body1030and a space-out mechanism1000. The space-out mechanism1000may include a first ramp ring1040, a second ramp ring1090, and a piston1050. The piston1050may include ramp surfaces1055and rotational stop surfaces1056.

Further, the first ramp ring1040may include lower ramp surfaces1042and an upper ramp surface1046. The lower ramp surfaces1042may contact the ramp surfaces1055of the piston1050, and in one or more embodiments, the ramp surfaces1042of the ramp ring1040and the ramp surfaces1055of the piston1050may match in number and taper. By way of example, in one or more embodiments, the ramp ring1040may include multiple ramp surfaces1042each extending 120° circumferentially about the ramp ring1040. However, one of ordinary skill in the art will understand that in other embodiments, the ramp ring may have a single ramp surface and a single rotational stop surface or any combination of equal numbers of ramp surfaces and rotational stop surfaces that match the number of ramp surfaces and rotational stop surfaces of the piston. Further, in one or more embodiments of the present disclosure, the ramp surfaces1042,1055may all have a constant 4° taper. However, one of ordinary skill in the art will understand that in other embodiments the ramp surface may include steps or ridges and/or may have a constant or changing taper in the range of 0.5°-7°. Additionally, the upper ramp surface1046of the first ramp ring1040may have a constant taper. In one or more embodiments, the upper ramp surface1046may have a constant taper of 0.5°. However, one of ordinary skill in the art will understand that in other embodiments the ramp surface may include steps or ridges and/or may have a constant or changing taper in the range of 0.5°-7°. Further, a pin blind hole1047may be formed on the upper ramp surface1046.

Furthermore, the second ramp ring1090may include a lower ramp surface1091and an upper contact surface1092. The lower ramp surface1091of the second ramp ring1090may contact and may match the taper of the upper ramp surface1046of the first ramp ring1040. As discussed above, the lower ramp surface1091may have a constant taper of 0.5°. However, one of ordinary skill in the art will understand that in other embodiments the lower ramp surface1091may include steps or ridges and/or may have a constant or changing taper in the range of 0.5°-7° that matches that of the upper ramp surface1046of the first ramp ring1040. Further, a pin blind hole1093may be formed on the lower ramp surface1091and may be coaxially aligned with the pin blind hole1047of the first ramp ring1040during assembly. Further, a shear pin1095may be disposed within the aligned pin blind holes1047,1093to rotationally lock the first ramp ring1040and the second ramp ring1090until a sufficient piston force is applied to either the first ramp ring1040or the second ramp ring1090to shear the shear pin1095when locking and rigidizing the tubing hanger system1020within a wellhead housing.

Additionally, the tubing hanger body1030may include a downward facing contact surface1035. The downward facing contact surface1035of the tubing hanger body1030may contact upper contact surface1092of the second ramp ring1090at least when the tubing hanger system1020is run-in and when the tubing hanger system1020is in a fully locked and rigidized position within the wellhead housing.

Referring now toFIG.11, a tubing hanger locking system1100, according to one or more embodiments of the present disclosure, is illustrated. The tubing hanger locking system1100may include, at least, a piston1110, locking dogs1120, and a wedge1130. The piston1110, the locking dogs1120, and the wedge1130may be configured and coupled such that the tubing hanger locking system1100locks a tubing hanger in place within a wellhead housing and rigidizes a tubing hanger and casing hanger within the wellhead housing.

While one or more embodiments of the present disclosure may include a piston50,550,650,750,850,950,1050, one of ordinary skill would appreciate that in other embodiments, a space-out mechanism of a tubing hanger system may instead include a lower member, which may be a non-actuating member. However, as discussed above with respect to pistons of one or more embodiments of the present disclosure, the lower member may include, at least, ramp surfaces and rotational stop surfaces and may be configured to interact with a ramp ring in order to lock a casing hanger and a tubing hanger system in place within a wellhead housing and rigidize the system.

It should be understood that the present disclosure contemplates a method to lock and rigidize a tubing hanger system and casing hanger within a wellhead housing. The present disclosure also contemplates a method to assemble a tubing hanger system.

In one or more embodiments of the present disclosure, assembly of the tubing hanger system may include disposing a space-out mechanism about a first sealing profile and second sealing profile of a tubing hanger body. Further, in one or more embodiments where the space-out mechanism includes a ramp ring and a piston, a ramp ring may be disposed about the second sealing profile of the tubing hanger body. Then, in one or more embodiments including a safety mechanism for locking a rotation of the ramp ring relative to the tubing hanger body, the portions of the safety mechanism in the ramp ring and in the tubing hanger body may be aligned and coupled. This may further include disposing a safety lock spring in a pin blind hole, disposing a safety lock pin on top of the safety lock spring in the pin blind hole, and disposing a pin securing mechanism into the opening of the pin blind hole. Further, once the safety mechanism for locking a rotation of the ramp ring relative to the tubing hanger body is properly aligned and the safety lock pin is inserted into the pin counterbore of the tubing hanger body, a safety lock rod may be disposed within an elongated hole in the tubing hanger body. Further, if a space-out mechanism requires a pre-load to be applied to a mechanism configured to rotate the ramp ring relative to the tubing hanger body, the pre-load will be applied before rotationally locking the ramp ring and the tubing hanger body by way of the safety mechanism.

Then, in one or more embodiments, a piston may be disposed about the first sealing profile and the second sealing profile of the tubing hanger body. Once the piston is properly installed such that the seals of the tubing hanger body are properly located within the piston, the piston and the tubing hanger body may be aligned such that the anti-rotation pin may be threaded into the threaded pin borehole of the piston and extend into a pin slot of the tubing hanger body. Additionally, in one or more embodiments, a retainer ring may be disposed within a third groove of the tubing hanger body.

Additionally, in one or more embodiments of the present disclosure, locking and rigidizing a tubing hanger system and casing hanger within a wellhead housing may include running an assembled tubing hanger system into the wellhead housing, landing the tubing hanger system on the casing hanger and sealing a tubing hanger to casing hanger seal of the tubing hanger body against the casing hanger. Landing the tubing hanger system on the casing hanger may further include collapsing a retaining ring into a third groove of the tubing hanger body. Then, in one or more embodiments, a seal test on the tubing hanger to casing hanger seal may be performed. Once the seal test confirms that the seals are properly set, the tubing hanger may be locked. The process of locking the tubing hanger may activate the safety lock rod and engage the locking dogs into their locking profile within the wellhead housing. Then, the tubing hanger body may be lifted to preload the locking mechanism in place within the wellhead housing.

In one or more embodiments, the space-out mechanism may then be actuated, taking up any axial gaps created by lifting on the tubing hanger body and rigidizing the tubing hanger system within the wellhead housing. Actuating the space-out mechanism may further include unlocking a safety mechanism. Unlocking the safety mechanism may include compressing a safety locking rod into an elongated hole of the tubing hanger body and pushing a safety lock pin out of a pin counterbore of the tubing hanger body such that the ramp ring is no longer rotationally locked to the tubing hanger body. Actuating the space-out mechanism may further include moving the piston down to push against the casing hanger, rotating the ramp ring, and filling the gap between the piston and the tubing hanger body. Once the space-out mechanism has been activated to rigidize the tubing hanger body and the casing body within the wellhead housing, the casing hanger seal may be seal tested to ensure that it is still properly sealing. Then, finally, the tubing hanger system may be released.

Space-out mechanisms, as described at length above, may be used in other contexts as well to rigidize wellhead system components by removing any axial gaps in the wellhead system created during the process of landing/locking components of the wellhead system. For example, a space-out mechanism may be used to close out any axial gaps in a connection between a casing hanger and the wellhead housing (e.g., prior to landing a tubing hanger).

In some cases, machining tolerances may give rise to small gaps between a locking mechanism (e.g., lock ring) of a seal assembly and an upper edge of a complementary lock profile of the wellhead when the seal assembly is landed and locked to seal an annulus between the casing hanger and the wellhead. Such gaps may enable the seal assembly located between the casing hanger and the wellhead to move up and down axially in response to pressure differentials. Over time, this motion of the seal may cause undesirable wear on the seal, increasing the chance for failure.

To address this issue, a seal assembly1200, as depicted inFIG.12, may be equipped with a space-out mechanism1222used to reduce gaps and rigidize the system. The seal assembly1200may include an upper body1206, a lower body1214, an actuator sleeve1220, and a locking mechanism1216. The seal assembly1200may first be lowered into a wellhead. Once lowered, the seal assembly1220may land upon the casing hanger1224. Weight may be applied to the seal assembly1220via a running tool (not shown); this weight may cause the actuator sleeve1220to move downward with respect to the upper body1206and the locking mechanism1216, thereby pushing the locking mechanism1216into grooves of the inner diameter profile of the wellhead housing (not shown). Once the actuator sleeve1220has moved down, there may remain a gap between the locking mechanism1216and the uppermost edge of the grooves. To increase the rigidity of the system, it is desirable to reduce, minimize, or eliminate such a gap.

The seal assembly1200ofFIG.12includes a space-out mechanism1222, which may be coupled between the upper body1206and the lower body1214as shown. The upper body1206may be coupled to the locking mechanism1216. The lower body1214may land on a landing shoulder of the casing hanger1224. The lower body may include a seal1218, which may be rigidized in accordance with teachings of the present disclosure. The space-out mechanism1222may be utilized to increase the axial distance between the upper body1206and the lower body1214in order to ensure that (1) the seal1218has landed at the appropriate location; and (2) the locking mechanism1216is positioned against the upper edge of the corresponding profile of the inner diameter of the wellhead (not shown).

The space-out mechanism1222may include a ramp ring1202and an actuation mechanism1203. The actuation mechanism1203, in the illustrated embodiment, includes a spring and1210and a pressure-actuated release mechanism1212. The pressure-actuated release mechanism1212may be any mechanism suitable to prevent the lower body from descending until a threshold pressure is reached; for example, the pressure-actuated release mechanism1212may be a shear pin or other shearable actuation component.

In certain embodiments, the ramp ring1202may be configured to rotate relative to the upper body1206and the lower body1214. The ramp ring1202may comprise at least one tapered surface, and the upper body1206may comprise at least one tapered surface configured to interface with the at least one tapered surface of the ramp ring1202. The tapered surfaces of the ramp ring1202and the upper body1206may be complementary. Furthermore, the tapered surfaces of the ramp ring1202and the upper body1206may be configured to bear against each other to rigidize the system. In certain embodiments, the at least one taper of each of the ramp ring1202and the upper body1206may have a slope between 0.5° and 7°. The ramp ring1202of the space-out mechanism1222, according to one or more embodiments of the present disclosure, may include a lower contact surface configured to interface with an upper contact surface of the lower body1214. Additionally, in one or more embodiments, an upper surface of the ramp ring1202may have a plurality of ramp surfaces and a plurality of rotational stop surfaces. For example, the ramp ring1202may take the form of the ramp ring (e.g., ramp ring40) shown inFIG.3A, except that the ramp surfaces and stop surfaces are on the top of the ramp ring instead of the bottom. For example, in one or more embodiments, the ramp ring1202may include three ramp surfaces each extending 120° circumferentially about the ramp ring1202. However, one of ordinary skill in the art will understand that in other embodiments, the ramp ring1202may have a single ramp surface and a single rotational stop surface or any combination of equal numbers of ramp surfaces and rotational stop surfaces that match the number of ramp surfaces and rotational stop surfaces of the upper body1206. Further, in one or more embodiments of the present disclosure, the ramp surface(s) may have a constant 3.5° taper. However, one of ordinary skill in the art will understand that in other embodiments the ramp surface(s) may include steps or ridges and/or may have a constant or changing taper in the range of 0.5°-7°. Alternatively, the ramp surface(s) may include any range of angles, surface geometries, and/or coatings that prevent rotation once installed.

The ramp ring1202of the space-out mechanism1222may be configured to rotate via the spring1210relative to the upper body1206and the lower body1214. In one or more embodiments, the ramp ring1202may be rotationally coupled to the lower body1214by a circumferential spring mechanism (which may or may not be similar to the circumferential spring mechanism580ofFIG.5A) including the spring1210. The circumferential spring mechanism may be coupled to the ramp ring1202on a first end and to the lower body1214on a second end. The spring1210may be disposed within a circumferential groove (not shown) located on the lower body1214. Further, the spring1210may be directly coupled to the lower body1214by a spring connector (not shown) on a first end of the circumferential groove and may be coupled (e.g., via a transfer block, spring connector, and/or bolts) to the ramp ring1202.

In one or more embodiments, when assembling the seal assembly1200before run-in, the circumferential spring mechanism may be preloaded such that when a safety mechanism locking the upper body1206to the lower body is disengaged, the space-out mechanism1222self-actuates to rotate the ramp ring1202against the lower body1214to extend the space-out mechanism1222axially and remove any axial gaps that have formed during installation of the seal assembly1200into wellhead housing. When the space-out mechanism1222is actuated, the rotation of the ramp ring1202will cause the ramp surface(s) of the ramp ring1202to bear against and rotate against the corresponding ramp surface(s) of the upper body1206and extend the space-out mechanism1222axially.

The pressure-actuated release mechanism1212may be a safety mechanism configured to lock the upper body1206to the lower body1214until a pressure is applied to disengage the pressure-actuated mechanism1212. The pressure-actuated release mechanism1212may be any mechanism suitable to prevent the lower body1214from moving with respect to the upper body1206until a threshold pressure is reached; for example, the pressure-actuated release mechanism1212may be a shear pin. The shear pin may extend between the upper body1206and the lower body1214. The actuation mechanism1203of the illustrated embodiment including the spring1210and shear pin are purely exemplary—any actuation mechanism for the space-out mechanism1222may be used without departing from the scope of the present disclosure. For example, and without limitation, one or more of a spring1210, shear pin, other pressure-actuated release mechanism1212, piston, ratchet, rod, spring plate, arm, slider, rack, and pinion may be used for actuation, such as those described at length above with reference toFIGS.6A-10.

In certain embodiments, the space-out mechanism1222may include another safety mechanism according to one or more embodiments of the present disclosure. In particular, a spring-loaded rod1204disposed within the ramp ring40may be installed during assembly of the seal assembly1200and engage the upper body1206so as to rotationally lock the ramp ring1202to the upper body1206until the proper time in the seal assembly run-in sequence in which the ramp ring1202should be rotationally actuated in order to take up any axial space created by the installation procedure.

The safety mechanism may be similar to the safety mechanism illustrated in detail inFIG.4and described above. The only features of the safety mechanism illustrated inFIG.12are the spring-loaded rod1204(e.g., safety lock rod72ofFIG.4) and the corresponding pin securing mechanism1208(e.g., pin securing mechanism45ofFIG.4). It will be understood that the safety mechanism ofFIG.12may also include a safety lock pin (e.g.,70ofFIG.4) and a safety lock spring (e.g.,71ofFIG.4) disposed within the ramp ring1202. The spring-loaded rod1204may be disposed within the upper body1206. The ramp ring1202, in one or more embodiments, may include a pin blind hole disposed in an upper contact surface thereof with the pin securing mechanism1208disposed in the opening of the pin blind hole. Additionally, the upper body1206, in one or more embodiments, may include an elongated hole1209that extends from an upward facing contact surface thereof to a downward facing contact surface thereof. Further, a pin counterbore (not shown) may be sunk into the downward facing contact surface and concentric with the hole1209. The spring-loaded rod1204may be disposed within the hole1209.

The safety mechanism may function similar to the assembly illustrated inFIG.4and described above with reference toFIG.4. For example, in one or more embodiments of the present disclosure, when the seal assembly1200is assembled before run-in, the safety lock pin (not shown) may engage the pin counterbore (not shown). During the installation of the seal assembly1200within the wellhead housing, actuation of the locking mechanism1216may cause the actuator sleeve1220to compress the spring-loaded rod1204into the hole1209, which will cause the bottom end of the spring-loaded rod1204to push the safety lock pin out of the pin counterbore. Once the safety lock pin is removed from the pin counterbore, the upper body1206and the ramp ring1202will no longer be rotationally locked with respect to each other, thereby allowing the ramp ring1202to rotate relative to the upper body1206(along the respective ramp surfaces) in order to remove any axial gaps in the seal assembly1200created during the process of locking and sealing the casing hanger1224within the wellhead housing.

The illustrated assembly ofFIG.12may be utilized in a subsea wellhead system. In certain embodiments, the assembly ofFIG.12may be utilized by performing a sequence of steps—one exemplary sequence is provided below.

First, the seal assembly1200may be landed on the casing hanger1224in the wellhead housing (not shown). The actuator sleeve1220may then be engaged, thereby extending the locking mechanism in a radially outward direction to lock the seal assembly1200to the wellhead and releasing the spring-loaded rod1204so that the ramp ring1202and the upper body1206are rotationally uncoupled. The seal assembly1200may then be pulled up via a seal assembly running tool (not shown).

Once the seal assembly1200is raised up such that the locking mechanism1216is engaged against the top of the inner profile on the wellhead, there may be a gap present between the lower body1214and the landing shoulder at the top of the casing hanger1224. Accordingly, pressurized fluid may be pumped down an annulus between the outer diameter of the stem of the running tool and the inner diameter of the upper body1206and lower body1214. The pressurized fluid may apply pressure to the inner diameter of the seal1218at the bottom of the lower body1214, thereby causing the lower body1214to begin to descend. The lower body's movement may actuate the pressure-actuated release mechanism1212(e.g., shearing a shear pin), allowing the lower body1214to further descend with respect to the upper body1206. Once the lower body1214has descended, the ramp ring1202and spring1210may automatically facilitate the closing of the gap.

Finally, the casing hanger/seal assembly running tool may be retrieved. The above list of steps should be understood as non-limiting—additional steps may be added or removed without departing from the scope of the present disclosure. Moreover, steps may be executed in a different order without departing from the scope of the present disclosure.

Locking mechanisms, as already explained in detail above, may be used to lock the tubing hanger assembly to the inner wall of the wellhead housing. Alternatively, in certain embodiments, locking mechanisms may also be used to lock the casing hanger assembly to the inner wall of the wellhead housing. When using a traditional type of locking system with a tubing hanger or casing hanger that has an automatic space-out mechanism, significant pre-load may not be able to be developed on the hanger assembly, e.g., from pressure from below. For example, significant pre-load may be about 100,000 lbs, about 1,000,000 lbs, or any other suitable value. Referring now toFIGS.13A-16C, a locking mechanism1320may be employed to address this issue, i.e., to lock a hanger assembly1300against a wellhead housing1302as well as preload the hanger assembly1300with a desired level of pre-load, for example, so as to enhance rigidization of the wellhead system. The hanger assembly1300may include an upper body1304, a main body1306, and a lower body1308. The lower body1308may first be landed within the wellhead housing1302. The main body1306may then be landed upon the lower body1308within the wellhead housing1302. The locking mechanism1320may be landed upon the main body1306within the wellhead housing1302. Lastly, the upper body1304may be coupled to the main body1306within the wellhead housing1302. The wellhead housing1302may include a central bore1310having a locking profile1312disposed thereon. The locking mechanism1320may engage the locking profile1312of the wellhead housing1302in order to lock the hanger assembly1300in place within the wellhead housing1302and rigidize the system. In one or more embodiments, the locking mechanism1320may include a lock ring1322and an actuator1324. The locking mechanism1320may be run into the wellhead housing1302until the locking mechanism1320abuts an upward-facing contact surface1314of the main body1306. In one or more embodiments, a bottom surface of the lock ring1322may directly abut the upward-facing contact surface1314and may be pushed outward in a radial direction into the locking profile1312of the wellhead housing1302by a compressive force caused by the actuator1324pushing down axially on the lock ring1322. In particular, the lock ring1322may have ridges1326disposed on its outer surface that may match the locking profile1312disposed along the central bore1310of the wellhead housing1302.

The lock ring1322may be actuated by the actuator1324via an interface between the lock ring1322and the actuator1324. The interface, according to one or more embodiments of the present disclosure, may allow axial force from the actuator1324to be transferred through the interface into outward radial expansion of the lock ring1322toward the locking profile1312on the inner diameter of the wellhead housing1302. In particular embodiments, the interface may be designed to achieve a so-called two-stage locking. For example, the interface may be shaped such that (1) axially downward movement of the actuator1324from a starting position to an intermediate position may actuate the lock ring1322into the locking profile1312; and (2) axially downward movement of the actuator1324from the intermediate position to a pre-load position may apply a pre-load to the hanger assembly1300, the details of which will be discussed further below.

In the illustrated embodiment, the interface may include a single tapered surface1328of the actuator1324that is angled from vertical such that an upper portion of the actuator1324may have a greater diameter than a lower portion of the actuator1324. As an example and not by way of limitation, the single tapered surface1328may be angled less than 4 degrees from vertical. As another example and not by way of limitation, the single tapered surface1328may be angled less than 2 degrees from vertical. Alternatively, one of ordinary skill in the art would understand that in other embodiments, the single tapered surface1328may be angled at any suitable angle from vertical without departing from the scope of the present disclosure. In the illustrated embodiment, the interface may also include an inner surface1330of the lock ring1322that is tapered to match the single tapered surface1328of the actuator1324. When the actuator1324moves down in the axial direction, the single tapered surface1328may contact and press against the inner surface1330of the lock ring1322, pushing the lock ring1322radially outward (by a horizontal component of the pressing force acting through the interface) until the lock ring1322engages into the locking profile1312.

In one or more embodiments, axial downward movement of the actuator1324may be interrupted by a split ring1332such that the actuator1324is temporarily stopped at its intermediate position. In the illustrated embodiment, the split ring1332may be disposed along a radially inner surface of the upper body1304. For example, the split ring1332may be disposed within a groove1316of the upper body1304and may have an unretracted outer diameter that is greater than the diameter of the upper body1304. Axial location of the split ring1332may be disposed below the actuator1324in its starting state. This position of the split ring1332may be such that the upper portion of the actuator1324cannot contact the lock ring1322until the split ring1332is collapsed into the groove1316. Further, the split ring1332may have an upper contact surface that is tapered such that additional downward forces from the actuator1324as it travels past the intermediate position during actuation may push on the upper contact surface and cause the split ring1332to retract into the groove1316. In the retracted state, the radially outer surface of the split ring1332may stay flush with or short of the surface of the upper body1304, thereby opening a passage for the actuator1324to press down further, e.g., past the split ring1332to the pre-load position. Thus, in one or more embodiments, the split ring1332needs to be retracted or collapsed in order for the actuator1324to be able to travel to the pre-load position. Although the present disclosure describes a hanger assembly with a split ring in a particular manner, the present disclosure contemplates hanger assemblies with any suitable split rings in any suitable manner. For example, additional or alternative to the split ring1332disposed in the upper body1304, a split ring may be arranged in a running tool (not shown), which serves to apply weight to the actuator1324, causing the actuator1324to move downward. In particular, the split ring may stay in its unretracted state under low pressure, causing the actuator1324to stop at the intermediate position, and may yield as more weight in the running tool is applied, thereby allowing the actuator1324to move past the intermediate position when pre-loading the hanger assembly1300within the wellhead housing1302.

In certain embodiments, the hanger assembly1300may include another stopper, e.g., for temporarily stopping the actuator at its intermediate position according to one or more embodiments of the present disclosure. As an example, a shear pin may be disposed at the radially inner surface of the upper body1304to block travel path of the actuator1324at the intermediate position until a sufficient actuation force is applied to further press down the actuator1324and shear the shear pin when pre-loading the hanger assembly1300within the wellhead housing1302. As another example, a shear pin may be disposed in a running tool (not shown), which serves to apply weight to the actuator1324, causing the actuator1324to move downward. In particular, the shear pin may prevent movement of the actuator1324past the intermediate position until additional weight is added in the running tool to shear the shear pin when pre-loading the hanger assembly1300within the wellhead housing1302. It should be understood that the shear pins described above are purely exemplary. Any suitable stopper feature may be employed without departing from the scope of the present disclosure. For example, one or more of a lock, a spring, a ring, a pin, a ratchet, or the like may be employed additionally or alternatively to temporarily retain the actuator1324at the intermediate position.

The hanger assembly1300as illustrated may include a space-out mechanism1340disposed between the main body1306and the lower body1308, for example, to close out axial gaps in the wellhead and rigidize the system. In one or more embodiments, the space-out mechanism1340may include a ramp ring1342, which may be configured to rotate relative to the main body1306and the lower body1308, and a piston1344, which may interface the ramp ring1342. Specifically, the ramp ring1342may comprise at least one tapered surface1346, and the piston1344may comprise at least one tapered surface configured to interface with the at least one tapered surface1346of the ramp ring1342. The tapered surfaces of the ramp ring1342and the piston1344may be complementary. Furthermore, the tapered surfaces of the ramp ring1342and the piston1344may be configured to bear against each other to rigidize the system. In certain embodiments, the at least one taper of each of the ramp ring1342and the piston1344may have a slope between 0.5° and 7°. Additionally, in one or more embodiments, the ramp ring1342and the piston1344may take form similar to the ramp ring illustrated in detail inFIG.3Aand described above with reference toFIG.3A. When actuated, the ramp ring1342may rotate out, thereby expanding the space-out mechanism1340to remove any axial gaps in the wellhead system created during installation. In certain embodiments, the ramp ring1342may function similar to the ramp ring illustrated in detail inFIG.3Aand described above with reference toFIG.3A. Alternatively, the ramp ring1342may function similar to the ramp ring illustrated in detail inFIG.12and described above with reference toFIG.12.

In certain embodiments, the hanger assembly1300may include a space-out mechanism release assembly1350configured to selectively release the space-out mechanism1340so that the space-out mechanism1340can actuate. In particular, a lever-actuated pin1352disposed within the main body1306may be installed during assembly of the hanger assembly1300and engage the ramp ring1342so as to rotationally lock the ramp ring1342to the main body1306until the proper time in the hanger assembly1300run-in sequence in which the ramp ring1342should be rotationally actuated in order to take up any axial space created by the installation procedure. Specifically, the lever-actuated pin1352may be levered to retract up and out of engagement with the ramp ring1342by a trigger rod1354. In one or more embodiments, one end of the trigger rod1354may be coupled to the lever-actuated pin1352while the other end of the trigger rod1354may be coupled to the actuator1324. Upon the actuator1324descending from the starting position to the intermediate position, the trigger rod1354may be pushed downward to lift up the lever-actuated pin1352, thereby unlocking the ramp ring1342such that the ramp ring1342may be rotationally actuated as needed.

Alternatively, the space-out mechanism release assembly1350may be configured similar to the safety mechanism illustrated in detail inFIG.4and described above with reference toFIG.4. For example, in certain embodiments, the space-out mechanism release assembly1350may be spring-loaded, pressure-actuated, or movable in any suitable manner without departing from the scope of the present disclosure in order to selectively retain or release the space-out mechanism1340.

The embodiments illustrated inFIGS.13A through16Cmay be utilized in a subsea wellhead system. However, similar techniques may be used in land-based wellhead assemblies as well. In certain embodiments, the assembly ofFIGS.13A-16Cmay be utilized by performing a sequence of steps—one exemplary sequence is provided below.

First, the hanger assembly1300may be landed into and engaged with the wellhead housing1302. Once the hanger assembly1300is in position, the running tool may be actuated with low pressure, causing the actuator1324to move downward with respect to the main body1306and the lock ring1322, thereby expanding the lock ring1322radially towards and into the locking profile1312of the wellhead housing1302. In particular, the actuator1324may move from the starting position until stopped at the intermediate position by the split ring1332. Then, the space-out mechanism1340may be released for actuation. In one or more embodiments, the release of the space-out mechanism1340may occur in response to the actuator1324moving from the starting position to the intermediate position. For example, as the actuator1324descends, the trigger rod1354coupled to the actuator1324may push on the lever-actuated pin1352, thereby unlocking the space-out mechanism1340by rotationally uncoupling the ramp ring1342and the main body1306so that the space-out mechanism1340may actuate as needed. Overpull may be applied on the running tool to pull up the hanger assembly1300. In some embodiments, the overpull may pull about 50,000 lbs of tension. Of course, other suitable levels of overpull may be applied without departing from the scope of the present disclosure. Lifting the hanger assembly1300in the vertical direction may cause the upper surface of the lock ring1322to engage on the locking profile1312(e.g., on a topmost lockdown groove of the locking profile1312) of the wellhead housing1302. This may confirm that the hanger assembly1300is locked into the wellhead housing1302and the space-out mechanism1340will activate (e.g., via the piston1344). Then, the overpull may be maintained to retain the hanger assembly1300at the lifted position. Pressure is exerted to seal the main body1306. In certain embodiments, this may be performed in a way similar to the method described above with reference toFIG.12. Upon sealing, the piston1344may be pressurized, thereby maintaining the space-out mechanism1340in its actuated position, thus ensuring proper space-out. Following confirmation that the main body1306is properly sealed and spaced out, pre-load may be applied to the hanger assembly1300. In certain embodiments, the lock ring1322may be subjected to a pressure of about 15,000 psi or other suitable levels of pressure. This will expand the lock ring1322further into the locking profile1312of the wellhead housing1302and add significant pre-load to the hanger assembly1300. In certain embodiments, the pre-load on the hanger assembly1300may be up to 100,000 lbs. Of course, other suitable levels of pre-load on the hanger assembly1300are also contemplated without departing from the scope of the present disclosure. Finally, the overpull may be removed, and the running tool may be unlatched and retrieved. The above list of steps should be understood as non-limiting—additional steps may be added or removed without departing from the scope of the present disclosure. Moreover, steps may be executed in a different order without departing from the scope of the present disclosure.

Referring now toFIGS.17A-17D, interaction of a lock ring1722and an actuator1724, according to one or more embodiments of the present disclosure, during installation is illustrated. The installation may be performed following the steps and sequence described with reference toFIGS.13A,14A,15A, and16A. Alternatively, as will be appreciated by one of skill in the art, the installation may be performed using less or more steps or executed in a different sequence without departing from the scope of the present disclosure. In the illustrated embodiments, the interaction of the lock ring1722and the actuator1724may occur via an interface1700. The interface1700may include two flat surfaces1726,1728of the actuator1724that are separated by a step1730. For example, the two flat surfaces1726,1728, and the step1730may be formed on the outer surface of the actuator1724such that an upper portion of the actuator1724may have a greater diameter than a lower portion of the actuator1724. While described as being flat, the two surfaces1726,1728in some embodiments may alternatively be angled, tapered, or otherwise inclined from vertical if needed. Furthermore, the step1730may be slightly tapered as shown, or alternatively form an angle of about 90 degrees relative to the vertical. In one or more embodiments, the lock ring1722may have an inner surface that is shaped to match the outer surface of the actuator1724. As a non-limiting example, the lock ring1722may also be structured with two flat surfaces separated by a step. During installation, at the starting position of the actuator1724, the actuator1724may be spaced from contact the lock ring1722. Actuating the actuator1724(e.g., under low pressure) may first cause the flat surface1726to contact the lock ring1722until the step1730catches an upper rim of the lock ring1722when the actuator1724moves from the starting position to the intermediate position. As the actuator1724continues to press down on the lock ring1722and moves from the intermediate position to the pre-load position (e.g., following the overpull and actuation of a space-out mechanism as described at length above), the flat surface1728may push against the lock ring1722to further expand the lock ring1722radially into the lock profile1712, thereby adding a pre-load to the system.

Referring now toFIGS.18A-18D, interaction of a lock ring1822and an actuator1824, according to one or more embodiments of the present disclosure, during installation is illustrated. The installation may be performed following the steps and sequence described with reference toFIGS.13A,14A,15A, and16A. Alternatively, as will be appreciated by one of skill in the art, the installation may be performed using less or more steps or executed in a different sequence without departing from the scope of the present disclosure. In the illustrated embodiments, the interaction of the lock ring1822and the actuator1824may occur via an interface1800. The interface1800may include a flat surface1826of the actuator1824and a tapered surface1828of the actuator1824. The flat surface1826may be located vertically below the tapered surface1828such that an upper portion of the actuator1824may have a greater diameter than a lower portion of the actuator1824. The flat surface1826and the tapered surface1828may be continuously connected or otherwise separated by a step (not shown). In one or more embodiments, the lock ring1822may have an inner surface that is shaped to match the outer surface of the actuator1824. As a non-limiting example, the lock ring1822may also be structured with a flat surface and a tapered surface. During installation, at the starting position of the actuator1824, the actuator1824may be spaced from contact the lock ring1822. Actuating the actuator1824(e.g., under low pressure) may first cause the flat surface1826to contact the lock ring1822until the connection between the flat surface1826and the tapered surface1828contacts an upper rim of the lock ring1822when the actuator1824moves from the starting position to the intermediate position. As the actuator1824continues to press down on the lock ring1822and moves from the intermediate position to the pre-load position (e.g., following the overpull and actuation of a space-out mechanism as described at length above), the tapered surface1828may push against the lock ring1822to further expand the lock ring1822radially into the lock profile1812, thereby adding a pre-load to the system.

Referring now toFIGS.19A-19D, interaction of a lock ring1922and an actuator1924, according to one or more embodiments of the present disclosure, during installation is illustrated. The installation may be performed following the steps and sequence described with reference toFIGS.13A,14A,15A, and16A. Alternatively, as will be appreciated by one of skill in the art, the installation may be performed using less or more steps or executed in a different sequence without departing from the scope of the present disclosure. In the illustrated embodiments, the interaction of the lock ring1922and the actuator1924may occur via an interface1900. The interface1900may include a tapered surface1926of the actuator1924. The tapered surface1926may be sloped from vertical at a low angle such that an upper portion of the actuator1924may have a slightly greater diameter than a lower portion of the actuator1924. As an example and not by way of limitation, the tapered surface1926may be angled less than 4 degrees from vertical. As another example and not by way of limitation, the tapered surface1926may be angled less than 2 degrees from vertical. Alternatively, one of ordinary skill in the art would understand that in other embodiments, the single tapered surface1926may be angled at any suitable angle from vertical without departing from the scope of the present disclosure. In one or more embodiments, the lock ring1922may have an inner surface that is shaped to match the outer surface of the actuator1924. As a non-limiting example, the lock ring1922may also be structured with a tapered surface that is sloped from vertical at a low angle. During installation, at the starting position of the actuator1924, the actuator1924may be spaced from contact the lock ring1922. Actuating the actuator1924from the starting position to the intermediate position as well as from the intermediate position to the pre-load position may cause the tapered surface1926to contact the lock ring1922to expand the lock ring1922radially into the lock profile1912.

It should be understood that the present disclosure contemplates a method to lock and rigidize a seal assembly and casing hanger within a wellhead housing. The present disclosure also contemplates a method to assemble a seal assembly.

In one or more embodiments of the present disclosure, assembling the seal assembly may include disposing a space-out mechanism between an upper body and a lower body of the seal assembly. Then, in one or more embodiments including a safety mechanism for locking a rotation of the ramp ring relative to the upper body, the portions of the safety mechanism in the ramp ring and in the upper body may be aligned and coupled. This may further include disposing a safety lock spring in a pin blind hole, disposing a safety lock pin on top of the safety lock spring in the pin blind hole, and disposing a pin securing mechanism into the opening of the pin blind hole. Further, once the safety mechanism for locking a rotation of the ramp ring relative to the upper body is properly aligned and the safety lock pin is inserted into the pin counterbore of the tubing hanger body, a spring-loaded rod may be disposed within an elongated hole in the upper body. Further, if a space-out mechanism requires a pre-load to be applied to a mechanism configured to rotate the ramp ring relative to the upper body, the pre-load will be applied before rotationally locking the ramp ring and the upper body by way of the safety mechanism.

Then, in one or more embodiments, a pressure-actuated release mechanism is used to secure the upper body to the lower body in an axial direction, with the ramp ring between a lower edge of the upper body and an upper edge of the lower body.

Additionally, in one or more embodiments of the present disclosure, locking and rigidizing the seal assembly and casing hanger within a wellhead housing may include running an assembled seal assembly into the wellhead housing, landing the seal assembly on the casing hanger and sealing a seal of the seal assembly between the casing hanger and the wellhead housing. The seal assembly may then be locked to the wellhead housing. The process of locking the seal assembly may engage the locking mechanism into its locking profile within the wellhead housing. At the same time, the process of locking the locking mechanism may unlock a safety mechanism by compressing a spring-loaded rod into an elongated hole of the upper body and pushing a safety lock pin out of a pin counterbore of the upper body such that the ramp ring is no longer rotationally locked to the upper body. Then, the seal assembly may be lifted to preload the locking mechanism in place within the wellhead housing.

In one or more embodiments, the space-out mechanism may then be actuated, taking up any axial gaps created by lifting on the seal assembly and rigidizing the seal assembly within the wellhead housing. Actuating the space-out mechanism may further include pressuring down an annulus between the casing hanger and a seal on the lower body to apply a downward force to the lower body, thereby shearing a pressure-actuated mechanism to enable the lower body to move downward with respect to the upper body. Moving the lower body in this manner causes the ramp ring to rotate, filling the gap between the lower body and the upper body. Once the space-out mechanism has been activated to rigidize the seal assembly and the casing body within the wellhead housing, the casing hanger seal may be seal tested to ensure that it is still properly sealing. Then, finally, the seal assembly may be released.

The disclosure includes the following illustrative embodiments.

A seal assembly, including: an upper body; a lower body having a seal for sealing between a first wellhead system component and a second wellhead system component; and a space-out mechanism disposed between the upper body and the lower body, the space-out mechanism including a ramp ring having at least one tapered surface, wherein the upper body has at least one tapered surface configured to interface with the at least one tapered surface of the ramp ring, wherein the ramp ring is configured to rotate relative to the upper body and the lower body, and wherein the at least one tapered surface of the ramp ring and the at least one tapered surface of the upper body are configured to bear against each other to rigidize the system.

The seal assembly provided above may include any one or more of the following features: Feature 1: the tapered surfaces of the ramp ring and the upper body are complementary. Feature 2: the taper of the at least one tapered surface of the ramp ring and the taper of the at least one tapered surface of the upper body have a slope between 0.5° and 7°. Feature 3: one or more of the ramp ring and the upper body have exactly three tapered surfaces. Feature 4: one or more pressure-actuated release mechanisms coupled between the upper body and the lower body. Feature 5: at least one of the one or more pressure-actuated release mechanisms is a shear pin. Feature 6: a spring coupled to the ramp ring and operable to circumferentially drive the ramp ring. Feature 7: a safety mechanism disposed at an interface of the upper body with the ramp ring, wherein the safety mechanism is configured to prevent rotation of the ramp ring with respect to the upper body until the safety mechanism is released.

A system including: a wellhead; a casing hanger disposed at least partially in the wellhead; and a seal assembly, including: a space-out mechanism, the space-out mechanism including a ramp ring having at least one tapered surface; an upper body having at least one tapered surface configured to interface with the at least one tapered surface of the space-out mechanism; and a lower body having a seal for sealing between the casing hanger and the wellhead, wherein the ramp ring is configured to rotate relative to the upper body and the lower body, and wherein the at least one tapered surface of the ramp ring and the at least one tapered surface of the upper body are configured to bear against each other to rigidize the system.

The system provided above may include any one or more of the following features: Feature 1: the tapered surfaces of the ramp ring and the upper body are complementary. Feature 2: the taper of the at least one tapered surface of the ramp ring and the taper of the at least one tapered surface of the upper body have a slope between 0.5° and 7°. Feature 3: one or more of the ramp ring and the upper body have three tapered surfaces. Feature 4: one or more pressure-actuated release mechanisms coupled between the upper body and the lower body. Feature 5: at least one of the one or more pressure-actuated release mechanisms is a shear pin. Feature 6: the wellhead is a subsea wellhead.

A method, including: running a seal assembly into a wellhead housing until the seal assembly lands on a casing hanger; locking the seal assembly to the wellhead housing; lifting the seal assembly; and actuating a space-out mechanism of the seal assembly to rigidize the seal assembly within the wellhead housing, wherein the space-out mechanism includes a ramp ring having at least one tapered surface, and wherein an upper body of the seal assembly has at least one tapered surface configured to interface with the at least one tapered surface of the space-out mechanism.

The method provided above may include any one or more of the following features: Feature 1: actuating the space-out mechanism expands at least a portion of the space-out mechanism to rigidize the tubing hanger system within the wellhead housing. Feature 2: actuating the space-out mechanism includes applying a pressure to the seal assembly to actuate one or more pressure-actuated release mechanisms. Feature 3: sealing a space between the wellhead housing and the casing hanger via a seal located on a lower body of the seal assembly. Feature 4: releasing a safety mechanism in response to movement of an actuator sleeve that locks the seal assembly to the wellhead housing, wherein the safety mechanism prevents rotation of the ramp ring with respect to the upper body until it is released.