One trip lockdown sleeve and running tool

The present application isThis patent application is for a broadening reissue of U.S. Pat. No. 11,072,984. U.S. Pat. No. 11,072,984 issued Jul. 27, 2021 from U.S. application Ser. No. 16/966,835 which was filed Jul. 31, 2020 asa U.S. National Stage Application of International Application No. PCT/US2020/012468 filed Jan. 7, 2020, which claims priority to U.S. Provisional Application Ser. No. 62/789,157 filed on Jan. 7, 2019both of which are incorporated herein by reference in their entirety for all purposes.The contents of these documents are hereby incorporated by reference herein.

The present disclosure relates generally to a lockdown sleeve and associated running tool and, more particularly, to a lockdown sleeve that can be run and secured in a wellhead in one trip.

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 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.

For various reasons, a 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. A lockdown mechanism, such as a lockdown sleeve, can be used to prevent axial movement of lire casing hanger in response to such axial forces.

Various types of lockdown sleeves have been conceived for axially interconnecting a casing hanger and a subsea wellhead. A lockdown sleeve, once run in and locked into the wellhead, prevents axial (i.e., vertical) movement of the uppermost casing hanger and seal assembly with respect to the wellhead. Typically, a lockdown sleeve is run into the wellhead on an associated running tool, landed on the casing hanger, and locked to a locking profile on an inner wall of the wellhead housing to axially secure the casing hanger within the wellhead. To install existing lockdown sleeves, 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. After retrieving the lead impression tool to the surface, the measured dimension can be obtained from the leads. With this information, the lockdown sleeve length can be adjusted at the surface so that once the lockdown sleeve is run in and secured to the wellhead, it provides a zero gap connection between the casing hanger and the wellhead housing and any desired pre-load.

This process of taking measurements in the wellhead via a lead impression tool, retrieving the tool to the surface, find then adjusting and installing a lockdown sleeve 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 lockdown sleeve and associated running tool that allow for a one-trip installation process.

Illustrative embodiments of the present disclosure are described in detail herein. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation specific decisions must be made to achieve developers' specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure. Furthermore, in no way should the following examples be read to limit, or define, the scope of the disclosure.

Certain embodiments of the present disclosure may be directed to a lockdown sleeve and a running tool that may be used to install the lockdown sleeve w within a wellhead in a single trip. The lockdown sleeve may include two pieces that are rotatably coupled together via threads such that the axial length of the lockdown sleeve can be adjusted by rotation of one portion of the lockdown sleeve relative to the other. The running tool may lower the lockdown sleeve into the wellhead, actuate the lockdown sleeve to lock against an inner wall of the high-pressure wellhead housing, and subsequently adjust the length of the lockdown sleeve so that the lockdown sleeve is fully landed on the casing hanger and applying any desired pre-load to the connection. The installation process for the lockdown sleeve tray be accomplished entirely during one trip into the wellhead with the running tool and the lockdown sleeve, as opposed to a first trip with a lead impression tool followed by an adjustment of the lockdown sleeve at the surface and a subsequent trip downhole to install the adjusted lockdown sleeve. 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 lockdown sleeve installation techniques.

The disclosed lockdown sleeve is installed by “weight set” on the running tool string. The weight set causes the expansion of the locking ring of the lockdown sleeve into the wellhead locking profile. After the locking ring is locked to the wellhead, the length of the lockdown sleeve can be adjusted by rotation (e.g., right-hand turns) to provide zero-gap and pre-load between the casing hanger, the lockdown sleeve, and the wellhead. The length of the lockdown sleeve is adjusted/set by the running tool while inside the wellhead during installation, exempting any length pre-set on the surface. The disclosed method for installation of the lockdown sleeve using the running tool allows for a BOP test to be performed when the running tool is landed on the lockdown sleeve. All these and other advantages will be apparent based on the following description.

Turning now to the drawings,illustrates certain components of a wellhead assembly. The illustrated wellhead assemblymay be a subsea wellhead assembly. However, similar techniques may be used in land-based wellhead systems as well. The wellhead assembly may include a wellhead(with high-pressure housing), an outer low-pressure housing, a lower casing hangerlanded within the wellheadand supporting an outer casing string, and an upper casing hangerlanded on the lower casing hangerand supporting an inner casing string. A c-ringor other attachment mechanism may support the lower casing hangerand thus the outer casingfrom the wellhead. A sealmay seal between the upper end of the upper casing hangerand the wellhead, thereby sealing the annulus about the inner casing string. The lower casing hangermay have its own sealas well for sealing with the wellhead. The wellhead, casing strings, and casing hangers as described are functionally similar to existing wellhead and casing hanger technologies. The wellhead assemblyinis typically used during production operations, and frequently a blowout preventer (BOP) or tieback connector is provided at the upper end of the wellhead.

The wellhead assemblyincludes a lockdown sleeve, which prevents axial movement between the upper casing hangerand the wellhead. The lockdown sleevelocks into an internal locking profile on a bore of the wellheadand lands on the upper casing hangerto secure and/or provide a pre-load to the casing hangerin a downward direction.provides a simplified illustration of the lockdown sleeve, but more detailed drawings of the lockdown sleeveand its constituent parts are provided in die following. The disclosed embodiments are directed to a lockdown sleevethat includes at least two portionsand, which can be rotated relative to each other to adjust an overall axial length L of the lockdown sleeve. An associated running tool may run the lockdown sleeveinto the wellhead, actuate the lockdown sleeveso that it is locked to the wellhead housing, and then, while still in the wellhead, adjust the length L of the lockdown sleeveso that the lockdown sleeve engages (and places any desired pre-load) on the upper casing hanger.

A more detailed description of the process for installing the lockdown sleeve in one trip will now be provided, with reference to. Each of these figures shows a different step in the installation process for the lockdown sleeve.

illustrate, among other things, the high-pressure wellhead housing, the casing stringsandand their associated casing hangersand, respectively, the lockdown sleeve, a running tool, and a jet sub. The running toolmay be used to install the disclosed lockdown sleevein a single trip to the wellhead.

The illustrations ofshow just one half of a cross section of the various wellhead assembly components, taken on one side of a longitudinal axisof the wellhead. As will be understood by those of ordinary skill in the art, the tools illustrated inextend entirely around the axis. The one-sided images are merely intended to simplify the drawings for a clear understanding of the various tool features.

As mentioned above, the lockdown sleevemay include two portions, e.g., a lower portionand an upper portion. The lower and upper portionsandmay be threaded together. Later during the installation process, the two portionsandof the lockdown sleevemay be rotated relative to each other to change an axial length of the lockdown sleeve. In addition to these two portionsand, the lockdown sleevemay include a lock ringconnected to the upper portionas well as in actuator ringconnected to the upper portion. The actuator ringmay function to cause the lock ringto expand radially outward (with respect to axis) to engage a locking profileon a radially inner wall of the wellhead housing. The lock ring, once in this expanded position engaged with the locking profile, locks the lockdown sleeveto the wellhead. A shear pinmay connect the actuator ringto the upper portionof the lockdown sleeve.

The running toolmay include a main bodythat attaches to a tool string at its upper end. The main body, as shown in, may be attached at its lower endto the jet sub. However, in other embodiments, the lower endof the main bodymay be attached to other wellbore tools or lengths of tubing, or may not be attached to anything. In addition to the main body, the running toolincludes a centralizer subcoupled to and extending in a radially outward direction (with respect to axis) from the main body. The centralizer subcenters the running toolas it is landed in the wellhead. A shear pinmay connect the centralizer subto the main bodyof the running tool. The centralizer submay have at least one axially oriented slotformed therethrough, and one or more keysextending from the main bodyof the running toolmay extend radially outward into the slot. Without limitations, there may be four axially oriented slotsdisposed 90° apart from each other. In embodiments, there may be four keysdisposed 90° apart from each other configured to extend into each of the respective slots. The key(s)extending into the sloton the centralizer submay maintain the centralizer subin a fixed circumferential orientation with respect to the main bodywhile allowing axial movement of die centralizer sub(after shearing the shear pin). In one or more embodiments, the one or more keysmay limit upward axial movement of the centralizer subafter at least one shear pinis sheared. In embodiments, there may be four retractable keys disposed 90° apart from each other and above the one or more keyswhich are responsible to fix rotational movement of the centralizer subduring the trip front surface to wellhead.

The main bodymay include one or more retractable keysdisposed thereon. The one or more retractable keys(s)may be configured to transfer string torque to the upper portionof the lockdown sleeveand to adjust the length of the lockdown sleeveto reach zero gap. In one or more embodiments, there may be lead blocks disposed about a bottom end of the centralizer subconfigured to indicate confirmation of full expansion of the lock ringwhen the running toolarrives on the surface. The lead blocks may be smashed during a turning or rotating step to reach zero gap and indicate the lockdown sleevehas been installed without a gap. In embodiments, the lead blocks may be disposed 90° apart from each other and 45° out of phase of the one or more retractable keys.

The main bodymay also include one or more spring-loaded pinsextending in a radially outward direction (with respect to axis) from the radially outer edge of the main body. A lower side of the spring-loaded pin(s)may feature a sloped edge, while an upper side opposite the lower side of the spring-loaded pin(s)features a straight (radially oriented) edge. That way, the spring-loaded pinis able to float over grooves/shoulders in the lockdown sleevewhen being moved in an axially downward direction relative to the lockdown sleeve, but then can be caught against these grooves/shoulders when being moved in an axially upward direction. Multiple spring-loaded pinsmay be positioned at different circumferential positions around the main body(all at the same axial location). The one or more spring-loaded pinsmay be retractable shear pins configured to lock the lockdown sleeveon the running toolonce the running toolhas landed in the lockdown sleeve.

The running toolmay also include a lock ring(or other similar locking component) that is captured within a circumferential recess (or groove) formed in the main body. The lock ringmay be biased in a radially outward direction (with respect to axis) such that the lock ringis able to expand partially into a corresponding circumferential recess (or groove)formed in the lower portionof the lockdown sleevewhenever the recessis axially aligned with the lock ring. When the running toolis positioned relative to the lockdown sleevesuch that the lock ringis not axially aligned with the recessin the lockdown sleeve, the lock ringis collapsed radially inwardly and held entirely within the corresponding recess of the main body. The lock ringmay function to keep the lockdown sleevein a fixed axial position with respect to the main bodyof the running tooluntil a time when it is desired to actuate the lockdown sleevein the wellhead.

shows the beginning of an installation process for the disclosed lockdown sleeveusing the associated running tool. The disclosed installation process may begin with lowering the running toolinto the wellhead with the lockdown sleevedisposed thereon. The jet submay be connected below the running tooland used to perform a jetting operation on the wellheadas needed. If the jet subis connected to the running tool, the installation process may involve jetting the wellheadusing the jet subbefore further lowering the running toolthrough the wellheadwith the attached lockdown sleeve.

After the jetting operation is completed, the installation process then involves further lowering and landing the lockdown sleeve, as shown in. Note that the following illustrations ofdo not show the jet sub. This is merely to simplify the drawings and not an indication that the jet subhas been removed during the installation process. As discussed above, the entire lockdown sleeve installation process takes place via a single trip into the wellhead.

shows the main bodyof the running toolbeing released from the lower portionof the lockdown sleeveto enable axial movement between the running tooland the lockdown sleeve. Specifically, the lock ringis retracted radially inward into the corresponding recess of the main bodyin response to a small amount of weight being set down on the running tool. This unlocks the main bodyfrom the lockdown sleeve, enabling axial movement of the running toolwith respect to the lockdown sleeve. Once the running toolis unlocked from the lockdown sleeve, the main bodyand attached centralizer subcan move downward (arrow) relative to the lockdown sleeve, as shown.

At some point, the centralizer subof the running toolengages an upper end of the actuator ringand pushes the lockdown sleevein a downward direction as well. This presses the lockdown sleevetoward a landing shoulderof the upper casing hanger.shows the lockdown sleevein a fully landed position against the shoulderof the casing hanger.

After initially landing the lockdown sleevevia the running tool, additional weight of the running string is applied to (set down on) the running tool. As shown in, this additional weight causes the running toolto move axially downward relative to the lockdown sleeve. The centralizer subof the running tooltransfers this axial downward force onto the actuator ringof the lockdown sleeve, since the lockdown sleeveis held stationary via the landing shoulderof the casing hanger. As more force is applied to the actuator ring, the shear pinlocated between the actuator ringand the upper portionof the lockdown sleeveis sheared. As a result, the actuator ringis able to move axially relative to the upper portionunder the force of the running toolto start an expansion of the lockdown sleeve lock ringon the high pressure wellhead housing.

The interface between the actuator ringand the lock ringmay include any profile that transfers downward axial force from the actuator ringinto outward radial expansion of the lock ring. For example, as shown, the actuator ringmay include a sloped wallthat slopes in a radially inward direction (with respect to axis) as it moves axially downward, and the lock ringmay include a complementary sloped wall. In general, the lock ringis a component that is biased in a radially inward direction but is actuatable in response to axially downward movement of the actuator ring. As the actuator ringmoves downward with respect to the lock ring, the lock ringis forced to flex radially outward into the locking profileof the wellhead. In embodiments, there may be one or more retractable shear pins configured to lock the actuator ringand to prevent the lock ringfrom moving back if the actuator ringis displaced back upward once it is in a fully downward position. The lock ringmay be a solid band of material that extends circumferentially almost entirely around the lockdown sleeve, but with a small break in the circumference to enable the lock ringto flex radially outward (e.g., a C-ring). In other embodiments, the lock ringmay have a collet-type construction that enables outward flexing of multiple fingers that are received in the locking profile. Other types of lock rings arc possible in other embodiments as well.

In, the lock ringis fully expanded into the locking profileof tire wellhead, in response to the running tool string load being applied to the running tool. The axial movement of the running toolwith respect to the lockdown sleeveduring this lock ring actuation step brings the one or more retractable keyson the main bodyinto contact with the upper portionof the lockdown sleeve. This causes the lead blocks at the bottom end of centralizer subto be fully smashed when the lock ringis fully expanded. At this time the lockdown sleevemay be locked on the wellheadwith its full lock-down capacity.

Once the lock ringis fully set in the locking profile, the centralizer subis halted from further downward movement. Increased weight down on the running toolat this point causes the shear pinbetween the main bodyand the centralizer subto shear. This enables axial movement of the main bodyof the running toolrelative to the centralizer subuntil the running toolis fully landed. Although axial movement is allowed, keysallow centralizer subupward axial movement to install the lockdown sleeveand avoid the centralizer subto disassemble from the main body. The one or more retractable keysplaced just above keysprohibit centralizer subrotation during the trip to wellhead, but after the shear pinsare sheared, the centralizer submay travel up and disengage from the one or more retractable keys. At this point, the centralizer submay centralize the main bodybut also allow main bodyto transfer the rotation of the string to the upper portionof the lockdown sleeve.

shows the running toolin this fully landed position, with the main bodylanded on a load shoulderon the lower portionof the lockdown sleeve. At this point, the string load may be slacked off the running tool.

All the downward weight that was previously transferred through the running toolto the lockdown sleeveduring the landing process may cause the lock ringto be engaged with a lowermost edge of the locking profile, as shown. This is not desirable, since the lockdown sleeveis intended to axially lock the casing hangerto the wellheadand this lock ringplacement at the lower edge of the locking profilemay enable upward axial movement of the casing hanger. As such, the method further includes adjusting an axial length of the lockdown sleeveso that the lockdown sleeveis engaged with both an upper edge of the locking profileon the wellheadand the shoulderof the casing hangerand applying any desired preload to the casing hanger connection.

Before adjusting the axial length of the lockdown sleeve, it may be desirable to perform an overpull operation on the lockdown sleeveto ensure that it has landed in the correct position and is locked to the high-pressure wellhead housing. This overpull operation is shown in. The running toolis pulled upward from the surface, causing the running toolto move axially upward with respect to the locked lockdown sleeve. As the main bodyof the running toolruns along a radially inner surface of the lockdown sleeve, the spring-loaded pinis biased radially outward into a groovewithin the lockdown sleeve. The straight edge of the spring-loaded pinmay transfer an upward pulling force to the upper portion, and therefore the lock ring, of the lockdown sleeve. If the lock ringis properly seated in the locking profile, the running toolwill be caught via this interaction with the spring-loaded pin, thereby confirming to an operator at the surface that the lockdown sleeveis set correctly.

Once it is confirmed that the lockdown sleeveis properly locked to the wellhead housing, it is desired to adjust the axial length of the lockdown sleeve. This may be accomplished via right-hand turns of the running toolwhile again putting weight down on the running tool. Once the shear pinshave been sheared, the centralizer submay disengage with the main bodyso that the main bodymay be rotatable without interference from the centralizer sub. Rotating the running toolmay cause the upper portionto rotate via the one or more retractable keyswith respect to the lower portionof the lockdown sleeve. With weight down on the running tooland lockdown sleeve, the lower portionof the lockdown sleeve remains stationary with respect to the wellheadwhile the upper portionof the lockdown sleeveis rotated. In embodiments, there may be one or more retractable keys disposed between the lower portionand the upper casing hanger. These one or more retractable keys may be configured to keep lower portionstationary with respect to the upper portion. This rotation causes the upper portionto ride up threadsat the threaded connection between the upper and lower portionsandof the lockdown sleeve, as shown in. This adjusts the axial length of the lockdown sleeveuntil it readies a zero-gap position (i.e., where the lock ringis engaged with an upper edge of the locking profilein the wellheadand the lower portionis engaged with the landing shoulder). Rotation may continue even after this zero-gap point is reached to apply a desired pre-load to tire casing hanger connection. Once the lockdown sleevelength has been adjusted, the running toolis now ready to test the BOP (not shown) during the same trip.

After installing the lockdown sleeve, and possibly testing the BOP, the running toolmay be retrieved to the surface. Specifically, the running toolmay be pulled upward (as during the overpull step described above) until the overpull force causes the spring-loaded pinto be sheared, thereby releasing the running toolfrom the lockdown sleeve. As shown in, the running toolmay then be retrieved to the surface, leaving the fully installed, zero-gap lockdown sleevein the wellhead. Again, this entire installation is accomplished during a single trip to the wellheadvia the running tool. The installation is performed without requiring a separate lead impression tool to be lowered to the wellhead to determine measurements for a subsequent surface-level adjustment of the lockdown sleeve.

Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the following claims.