Angle bolt pattern connector for wellhead systems

Abstract

A connector assembly for a wellhead, wherein the connector assembly includes a lower spool with a first radially-inner surface and an upper spool with a second radially-inner surface. The connector assembly also includes multiple fasteners configured to couple the lower spool and the upper spool to one another with an outer diameter that enables the connector assembly to fit through a blowout preventer (BOP) stack. The first radially-inner surface, the second radially-inner surface, or both include first features configured to support a first type of casing system in the connector assembly and second features configured to support a second type of casing system in the connector assembly.

Description

ANGLE BOLT PATTERN CONNECTOR FOR WELLHEAD SYSTEMSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 762171, titled “ANGLE BOLT PATTERN CONNECTOR FOR WELLHEAD SYSTEMS” and filed February 24, 2025, which is incorporated by reference herein in its entirety for all purposes.BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0003] Natural resources, such as oil and gas, are used as fuel to power vehicles, heat homes, and generate electricity. Once a desired natural resource is discovered below a surface, a mineral extraction system may be employed to access and extract the desired natural resource. The mineral extraction system may include a wellhead through which the desired natural resource is extracted. The wellhead may include or be coupled to a wide variety of components, such as a tubing hanger that supports a tubing, a casing hanger that supports a casing, valves, fluid conduits, and the like.SUMMARY

[0004] A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that theseaspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

[0005] In certain embodiments, a connector assembly for a wellhead, wherein the connector assembly includes a lower spool with a first radially-inner surface and an upper spool with a second radially-inner surface. The connector assembly also includes multiple fasteners configured to couple the lower spool and the upper spool to one another with an outer diameter that enables the connector assembly to fit through a blowout preventer (BOP) stack. The first radially-inner surface, the second radially-inner surface, or both include first features configured to support a first type of casing system in the connector assembly and second features configured to support a second type of casing system in the connector assembly.

[0006] In certain embodiments, a wellhead system includes a lower spool with multiple first openings and an upper spool with multiple second openings. The wellhead system also includes multiple fasteners, wherein each fastener of the multiple fasteners is configured to insert through a respective first opening of the multiple first openings and thread into a respective second opening of the multiple second openings to couple the lower spool and the upper spool to one another to form a connector assembly with an outer diameter that enables the connector assembly to fit through a blowout preventer (BOP) stack.

[0007] In certain embodiments, a method landing a connector assembly on one or more additional housing portions to form a wellhead housing, wherein the connector assembly comprises a lower spool, an upper spool, and multiple fasteners that couple the lower spool and the upper spool to one another with an outer diameter that enables the connector assembly to fit through a blowout preventer (BOP) stack. The method also includes running a casing hanger that supports a casing to land on a first feature of the lower spool. The method further includes placing a seal assembly that provides a seal for the casing hanger, wherein placing the seal assembly comprises utilizing a second lockingfeature of the upper spool to lock the seal assembly within the connector assembly without utilizing a third locking feature of the upper spool.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Various features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein:

[0009] FIG. 1 is a block diagram of a mineral extraction system, in accordance with an embodiment of the present disclosure;

[0010] FIG. 2 is a cross-sectional side view of an embodiment of a portion of a connector assembly that may be utilized in the mineral extraction system of FIG.1 , wherein a lower spool and an upper spool are aligned and separated from one another;

[0011] FIG. 3 is a cross-sectional side view of an embodiment of a portion of the connector assembly of FIG. 2, wherein the lower spool and the upper spool are aligned and in contact with one another;

[0012] FIG. 4 is a cross-sectional side view of an embodiment of a portion of the connector assembly of FIG. 2, wherein a fastener is positioned within respective openings of the lower spool and the upper spool;

[0013] FIG. 5 is cross-sectional side view of an embodiment of a portion of the connector assembly of FIG. 2, wherein the fastener is tightened to preload the fastener and cause the lower spool and the upper spool to be in an engaged configuration;

[0014] FIG. 6 is cross-sectional side view of an embodiment of a portion of a wellhead with the connector assembly of FIG. 2, wherein the connector assembly supports a split compact casing system;

[0015] FIG. 7 is cross-sectional side view of an embodiment of a portion of the wellhead of FIG. 6, wherein the connector assembly supports the split compact casing system and a tubing hanger;

[0016] FIG. 8 is cross-sectional side view of an embodiment of a portion of a wellhead with the connector assembly of FIG. 2, wherein the connector assembly supports a mandrel casing system;

[0017] FIG. 9 is cross-sectional side view of an embodiment of a portion of the wellhead of FIG. 8, wherein the lower spool and the upper spool are separated from one another to facilitate installation of a seal assembly for the mandrel casing system;

[0018] FIG. 10 is cross-sectional side view of an embodiment of a portion of the wellhead of FIG. 8, wherein the connector assembly supports the mandrel casing system and a tubing hanger;

[0019] FIG. 11 is cross-sectional side view of an embodiment of a portion of a wellhead with the connector assembly of FIG. 2, wherein the connector assembly supports a slip casing system, and the lower spool and the upper spool are separated from one another to facilitate installation of a seal assembly for the slip casing system;

[0020] FIG. 12 is cross-sectional side view of an embodiment of a portion of the wellhead of FIG. 11 , wherein the connector assembly supports the slip casing system and a tubing hanger; and

[0021] FIG. 13 is a flow diagram of an embodiment of a method of installing components of a wellhead that includes a connector assembly.DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0022] One or more specific embodiments of the present disclosure will be described below. These described embodiments are only exemplary of the present disclosure. Additionally, in an effort to provide a concise description of these exemplary embodiments, all features of an actual implementation may notbe described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers’ specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0023] When introducing elements of various embodiments of the present disclosure, articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” “having,” and “based on” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Any examples of operating parameters and / or conditions are not exclusive of other operating parameters and / or conditions of the disclosed embodiments.

[0024] Certain embodiments of the present disclosure generally relate to a connector assembly (e.g., angle bolt pattern connector assembly) for a wellhead. The connector assembly may be a multi-piece structure (e.g., housing) that fits within (e.g., through) a blowout preventer (BOP) stack. The connector assembly may include a lower spool (e.g., annular spool; first spool; casing spool) and an upper spool (e.g., annular spool; second spool; tubing spool). The lower spool may be configured to support a casing hanger(s), while the upper spool may be configured to support a tubing hanger(s).

[0025] The multi-pieces structure of the connector assembly may enable the connector assembly to transition between an engaged configuration and a disengaged configuration to support efficient casing installation operations, as well as maintenance operations. For example, the lower spool and the upper spool may be coupled together via fasteners (e.g., via inserting and tightening the fasteners), as well as separable from one another via the fasteners (e.g., vialoosening and withdrawing the fasteners). The fasteners may include multiple fasteners distributed about a circumference of the connector assembly, and the fasteners may be threaded fasteners (e.g., bolts; angle pattern bolts).

[0026] Advantageously, the connector assembly may have a slim diameter in the engaged configuration to enable the connector assembly to fit within the BOP stack. Additionally, the connector assembly may provide a sealed housing in the engaged configuration and may provide a separated housing in the disengaged configuration. With the separated housing in the disengaged configuration, an operator and / or a tool may access equipment (e.g., a casing hanger, a casing, a seal assembly) within the connector assembly to efficiently perform various operations, such as casing installation operations and / or maintenance operations. For example, the operator and / or the tool may access the equipment to address issues with the casing installation operations (e.g., casing stuck in a wellbore) without use of an internal cutter and / or other tools being lowered axially though the upper spool, for example.

[0027] Additionally, the connector assembly may provide flexibility to account for various factors, such as operator preferences and / or site conditions. In certain embodiments, the connector assembly may support various types of casing systems and enable running in of a casing hanger in a different order depending on the various factors. For example, the connector assembly may support a split compact casing hanger system that enables running in and sealing the casing hanger without removing the BOP stack. Additionally or alternatively, the connector assembly may support a mandrel casing hanger system that enables running in the casing hanger, and then removing the BOP stack to provide access to install a respective seal assembly to seal the casing hanger. Additionally or alternatively, the connector assembly may support a slip casing hanger system that enables running in casing, and then removing the BOP stack to provide access to install a slip assembly to hold the casing and a seal assembly to seal the slip assembly. These scenarios may be achieved using the connector assembly (e.g., the same connector assembly; the same lower spool, the same upper spool, and the same multiple fasteners). Additionally,the connector assembly may provide a short mandrel hanger seal and / or facilitate guiding to thereby block (e.g., prevent, reduce) hanger tilt.

[0028] FIG. 1 is a block diagram of an embodiment of a mineral extraction system 10. The mineral extraction system 10 may be utilized to access and / or extract various natural resources (e.g., hydrocarbons, such as oil and / or natural gas) from the earth. As illustrated, the mineral extraction system 10 includes a wellhead 12 (e.g., annular wellhead) coupled to a mineral deposit 14 via a wellbore 16.

[0029] As shown, the wellhead 12 includes a lower spool 18 (e.g., annular spool; first spool; casing spool; housing) that supports a casing hanger(s) 20. Each casing hanger 20 may support respective casing (e.g., a casing string) that is suspended in the wellbore 16. The wellhead 12 also includes an upper spool 22 (e.g., annular spool; second spool; tubing spool; housing) that supports a tubing hanger(s) 24. Each tubing hanger 24 may support respective tubing (e.g., a tubing string) that is suspended in the wellbore 16. As shown, the wellhead 12 may also include multiple fasteners 26 (e.g., threaded fasteners, such as a bolts), which may couple the lower spool 18 and the upper spool 22 to one another. For example, the multiple fasteners 26 may be tightened (e.g., installed) to cause the lower spool 18 and the upper spool 22 to be in an engaged configuration (e.g., connected; in contact; sealed). In the engaged configuration, the multiple fasteners 26 may block separation (e.g., axial separation of the lower spool and the upper spool from one another. Further, the multiple fasteners 26 may be loosened (e.g., removed) to cause the lower spool 18 and the upper spool 22 to be in a disengaged configuration (e.g., disconnected; separated; unsealed). In the disengaged configuration, the multiple fasteners may enable separation (e.g., axial separation) of the lower spool and the upper spool from one another. Together, the lower spool 18, the upper spool 22, and the multiple fasteners 26 may be considered to form a connector assembly 28 (e.g., a multi-piece structure; a multi-piece housing for the wellhead 12).

[0030] The mineral extraction system 10 may also include pressure control equipment 30 (e.g., a blowout preventer (BOP)). The wellhead 12 and the pressure control equipment 30 may provide respective bores that align with (e.g., fluidly couple to) the wellbore 16. Thus, a tool 32 may be inserted through one or more of the respective bores to carry out various operations. For example, the tool 32 may include a running tool that is configured to run the connector assembly 28 through the pressure control equipment 30 and land the connector assembly 28 as part of the wellhead 12. Further, the natural resources extracted from the mineral deposit 14 may flow through the respective bores and be routed via certain components of the pressure control equipment (e.g., routed into a flowline). To facilitate discussion, the mineral extraction system 10 and its components may be described with reference to an axial axis or direction 34, a radial axis or direction 36, and a circumferential axis or direction 38.

[0031] As discussed in more detail herein, a portion of the wellhead 12 may include or be formed by the connector assembly 28. The connector assembly 28 may be a multi-piece structure that fits within a BOP stack (e.g., of the pressure control equipment 30) and that may transition between the engaged configuration and the disengaged configuration to support efficient casing installation operations and maintenance operations, as well as to support different types of casing systems (e.g., split compact casing system, mandrel casing system, and / or slip casing system). In this way, the connector assembly 28 may facilitate access to equipment, as well as provide flexibility at installation (e.g., selection of a type of casing system among multiple different types of casing systems that may be used with the connector assembly 28).

[0032] FIGS. 2-5 illustrate components of the connector assembly 28. In particular, FIG. 2 is a cross-sectional side view of an embodiment of a portion of the connector assembly 28 that may be utilized in the mineral extraction system 10, wherein the lower spool 18 and the upper spool 22 are aligned and separated from one another. As shown, the lower spool 18 includes a respective radially inner surface 50 and a respective radially outer surface 52. Similarly, the upper spool 22 includes a respective radially inner surface 54 and a respective radiallyouter surface 56. Together, the respective radially inner surfaces 50, 54 may be considered to form a radially inner surface of the connector assembly 28. Together, the respective radially outer surfaces 52, 56 may be considered to form a radially outer surface of the connector assembly 28.

[0033] In FIG. 2, the respective radially inner surface 50 of the lower spool 18 includes surface features, such as one or more protrusions 58 (e.g., annular protrusions; shoulders), one or more annular seal elements 60, and so forth. The one or more protrusions 58 may support a casing hanger(s) (e.g., the casing hanger(s) 20 of FIG. 1) and / or provide fluid communication between spaces (e.g., for cement returns; pressure tests), while the one or more annular seal elements 60 may provide a seal (e.g., annular seal) against a casing string. The respective radially inner surface 54 of the upper spool 22 includes additional surface features, such as one or more grooves 62 (e.g., annular grooves; recesses). The one or more grooves 62 may be locking features that support a lock ring, support a tubing hanger (e.g., via the lock ring), and / or support other structures and / or operations.

[0034] The respective radially outer surface 52 of the lower spool 18 includes multiple recesses 64. For example, the multiple recesses 64 may be distributed (e.g., spaced apart from one another) about the circumferential axis 38. Each recess 64 includes a tapered surface 66. The tapered surface 66 may be described or defined in any suitable manner. For example, the tapered surface 66 may be described as having a lower end and an upper end along the axial axis 34, the lower end is proximate to the wellbore 16 of FIG. 1 when installed as part of the wellhead 12, the upper end is distal from the wellbore 16 of FIG. 1 when installed as part of the wellhead 12, and the lower end is radially outward of the upper end relative to the radial axis 36. As another example, the tapered surface 66 may be described as having the lower end and the upper end, and the tapered surface 66 extends radially inwardly from the lower end to the upper end.

[0035] As shown, each recess 64 also includes an additional tapered surface 68. The additional tapered surface 68 may be described or defined in anysuitable manner. For example, the additional tapered surface 68 may be described as having a lower end and an upper end along the axial axis 34, the lower end is proximate to the wellbore 16 of FIG. 1 when installed as part of the wellhead 12, the upper end is distal from the wellbore 16 of FIG. 1 when installed as part of the wellhead 12, and the lower end is radially inward of the upper end relative to the radial axis 36. As another example, the additional tapered surface 68 may be described as having the lower end and the upper end, and the additional tapered surface 68 extends radially outwardly from the lower end to the upper end. In certain embodiments, the tapered surface 66 and the additional tapered surface 68 may be transverse (e.g., orthogonal) to one another, such as oriented an angle 70 (e.g., approximately 90 degree angle) relative to one another. In this way, each recess 64 may generally provide an undercut section to receive a respective fastener 26 of FIG. 1.

[0036] Further, each recess 64 may include or be aligned with a respective opening 72 (e.g., through hole; devoid of threads) formed in the lower spool 18 and a respective opening 74 (e.g., blind hole; threads 76 along at least a portion of a length of the respective opening 74). For example, each recess 64 may be open to the respective opening 72 and the respective opening 74 along a respective axis 78. Thus, the connector assembly 28 may include the multiple recesses 64, multiple respective openings 72, and multiple respective openings 74 distributed about the circumferential axis 38.

[0037] In certain embodiments, a respective diameter 80 of the respective opening 72 may be different (e.g., greater; 1, 2, 3, 4, 5 or more percent greater) than a respective diameter 82 of the respective opening 74. As described herein, this difference in the respective diameters 80, 82 may facilitate sealing between the lower spool 18 and the upper spool 22, such as by energizing a seal element 84 (e.g., annular seal element) that is supported in or between opposed grooves 86 across an interface 88 (e.g., annular interface) between the lower spool 18 and the upper spool 22. The seal element 84 may be considered to be coupled to or to be part of the connector assembly 28.

[0038] As shown, the interface 88 includes multiple portions, including an outer portion 90 with outer axially-facing opposed surfaces, a tapered portion 92 with tapered opposed surfaces (e.g., with a taper that matches (e.g., aligns with, parallel to) the additional tapered surface 68), and an inner portion 94 with inner axially-facing opposed surfaces. In this configuration, the multiple portions may form a stepped arrangement of the interface 88 with the outer portion 90 offset from the inner portion 94 along the axial axis 34. Further, this configuration may facilitate alignment of the lower spool 18 and the upper spool 22 via multiple alignment pins 96 across the outer portion 90, energizing the seal element 84 at the inner portion 94, and / or favorable positioning of the respective fastener 26 of FIG. 1 (e.g., to provide a slim wellhead 12 of FIG. 1 and / or access to the respective fastener 26 of FIG. 1). The multiple alignment pins 96 may be considered to be coupled to or to be part of the connector assembly 28.

[0039] However, it should be appreciated that the interface 88 may have any of a variety of configurations (e.g., shapes, surfaces, portions), such as linear (e.g., straight) opposed surfaces that extend from the respective radially inner surfaces 50, 54 to the respective radially outer surfaces 52, 56. For example, the linear opposed surfaces may include axially-facing opposed surfaces that extend from the respective radially inner surfaces 50, 54 to the respective radially outer surfaces 52, 56 and / or that taper between the respective radially inner surfaces 50, 54 and the respective radially outer surfaces 52, 56. Additionally or alternatively, it should be appreciated that the multiple recesses 64 may have any of a variety of configurations (e.g., shapes, surfaces), such as with the respective tapered surfaces 66 being replaced with axially-extending surfaces and the respective additional tapered surfaces 68 being replaced with axially-facing surfaces. Further, the multiple recesses 64 may be configured such that instead of a respective recess 64 for each opening 72, a respective recess 64 may extend circumferentially about the lower spool 18 and expose (e.g., be open to) multiple openings 72 (e.g., 2, 3, 4, 5, 6, or more openings 72; less than all of the openings 72; discrete openings 72 spaced apart about the circumferential axis 38). Further, instead of the multiple recesses 64, one recess 64 may extendcircumferentially about the lower spool 18 and expose (e.g., be open to) multiple openings 72 (e.g., all of the openings 72; discrete openings 72 spaced apart about the circumferential axis 38).

[0040] FIG. 3 is a cross-sectional side view of an embodiment of a portion of the connector assembly 28, wherein the lower spool 18 and the upper spool 22 are aligned and in contact with one another. As shown, to transition from being separated as in FIG. 2 to being in contact as in FIG. 3, the upper spool 22 may be landed on the lower spool 18. The multiple alignment pins 96 may initially be placed in respective alignment grooves 98 distributed about the lower spool 18, and the upper spool 22 may be landed on the lower spool 18 such that the multiple alignment pins 96 are received in respective alignment grooves 98 distributed about the upper spool 22. In this way, the alignment pins 96 facilitate alignment of the lower spool 18 and the upper spool 22 (e.g., along the radial axis 36 and the circumferential axis 38), and thus, also facilitate alignment of the respective openings 72 of the lower spool 18 with the respective openings 74 of the upper spool 22 (e.g., along the radial axis 36 and the circumferential axis 38).

[0041] As shown in FIG. 3 and described in more detail herein, the multiple alignment pins 96, the different diameters 80, 82 of FIG. 2, and / or other features of the connector assembly 28 may enable or cause the respective openings 72 of the lower spool 18 to be at least partially offset from the respective openings 74 of the upper spool 22 at least upon landing the upper spool 22 on the lower spool 18 and prior to fastening the multiple fasteners 26 of FIG. 1. For example, with reference to the respective openings 72, 74 of FIG. 3, respective radially inner surfaces of the openings 72, 74 (e.g., along an upper side of the openings 72, 74) may provide a flush interface 97 (e.g., substantially flush, such as offset by less than a first distance), while respective radially inner surfaces of the openings 72, 74 (e.g., along a lower side of the openings 72, 74, wherein the lower side is opposite the upper side) may provide an offset interface 99 (e.g., not flush; offset equal to or more than the first distance).

[0042] FIG. 4 is a cross-sectional side view of an embodiment of a portion of the connector assembly 28, wherein a fastener 26 (e.g., threaded fastener, such as a bolt) is positioned within the respective opening 72 of the lower spool 18 and the respective opening 74 of the upper spool 22. As described herein, the connector assembly 28 includes the multiple fasteners 26 distributed about the circumferential axis 38. Thus, the fastener 26 is one example of the multiple fasteners 26 that may be utilized as part of the connector assembly 28. Further, the fastener 26 and each additional fastener 26 of the multiple fasteners 26 may insert into its own respective pair of openings 72, 74. Although various other configurations are envisioned, as noted herein.

[0043] As shown in FIG. 4, to insert the fastener 26, a shaft of the fastener 26 may be oriented along the axis 78. Then, a force may be applied to a head of the fastener 26 to drive the shaft of the fastener 26 through the respective opening 72. In certain embodiments, the respective opening 72 may be devoid of threads. Additionally, in certain embodiments, the respective opening 72 may have the respective diameter 80 and / or the offset interface 99 that provides a gap 100 (e.g., space along at least one side or portion of the shaft of the fastener 26 within the respective opening 72, such as along a lower side or portion of the shaft of the fastener 26 relative to the axial axis 34). Such features may facilitate efficient insertion of the fastener 26 to reach its position shown in FIG. 4.

[0044] Additionally, the threads 76 of the respective opening 74 may extend along all or a portion of the respective opening 74. As shown in FIG. 4, an initial portion of the respective opening 74 may be smooth or devoid of the threads 76 (e.g., the initial portion may be a portion proximate to the respective opening 72 of the lower spool 18) to facilitate efficient insertion of the fastener 26 through the respective opening 72 and into the respective opening 74 before threading the fastener 26 onto the threads 76 of the respective opening 74 as shown in FIG. 5.

[0045] In particular, FIG. 5 is cross-sectional side view of an embodiment of a portion of the connector assembly 28, wherein the fastener 26 is tightened to preload the fastener 26 and cause the lower spool 18 and the upper spool 22 tobe in an engaged configuration (e.g., connected; sealed). As shown, to transition to the engaged configuration, the fastener 26 may be rotated such that threads along the shaft of the fastener 26 engage the threads 76 of the respective opening 74 of the upper spool 22. Such tightening of the fastener 26 may energize the seal element 84, reduce (e.g., block, prevent, remove) space between the lower spool 18 and the upper spool 22 at the interface 88, and / or reduce (e.g., block, prevent, remove) the gap 100 of FIG. 4 (e.g., center or make more center the fastener 26 within the opening 72; reduce offset at the offset interface 99; shift the upper spool 22 radially inwardly relative to the lower spool 18).

[0046] In certain embodiments, upon complete tightening of the fastener 26, the head of the fastener 26 (e.g., an entirety of the head of the fastener 26) may be within the recess 64. Further, in certain embodiments, no portion of the fastener 26 extends radially outwardly from the respective radially outer surfaces 52, 56 of the lower spool 18 and the upper spool 22. Alternatively, in certain embodiments, only a small portion of the fastener 26 extends radially outwardly from the respective radially outer surfaces 52, 56 of the lower spool 18 and the upper spool 22 (e.g., less than about 2, 5, 10, 20, 30, or 50 millimeters). Thus, the fastener 26 is accessible, but protected, and also maintains a slim diameter of the connector assembly 28 for the wellhead 12 of FIG. 1.

[0047] In certain embodiments, the connector assembly 28 may be assembled into the engaged configuration at manufacturing. However, it should be appreciated that the connector assembly 28 may additionally or alternatively be assembled into the engaged configuration at a wellsite or at any other suitable location. Further, the connector assembly 28 be adjusted from the engaged configuration to a disengaged configuration (e.g., such as to transition from the engaged configuration of FIG. 5 to be separated as in FIG. 2, and then to be further separated to reach the disengaged configuration) such as to provide access between the lower spool 18 and the upper spool 22 along the axial axis 34 (e.g., insertion of a tool in the radial direction 36 between the lower spool 18 and the upper spool 22 along the axial axis 34).

[0048] As described herein, the connector assembly 28 shown and described with reference to FIGS. 2-5 may provide various advantages for the wellhead 12. First, the connector assembly 28 may have a slim diameter in the engaged configuration to enable the connector assembly 28 to fit within the BOP stack (e.g., of the pressure control equipment 30 of FIG. 1). Second, the connector assembly 28 may transition from the engaged configuration to the disengaged configuration via adjusting (e.g., unthreading) the multiple fasteners 26 to separate the lower spool 18 from the upper spool 22. Thus, advantageously, an operator and / or tools may access equipment (e.g., the casing hanger(s) 20 of FIG. 1, a casing string, a seal assembly, and so forth) within the connector assembly 28. Third, the connector assembly 28 may support various types of casing systems and enable running in of a casing hanger in a different order depending on various factors. For example, the connector assembly may support a split compact casing hanger system that enables running in and sealing a casing hanger without removing the BOP stack. Additionally or alternatively, the connector assembly may support a mandrel casing hanger system that enables running in a casing hanger, and then removing the BOP stack to provide access to install a seal assembly to seal the casing hanger. Additionally or alternatively, the connector assembly may support a slip casing hanger system that enables running in casing, and then removing the BOP stack to provide access to install a slip assembly to hold the casing and a seal assembly to seal the slip assembly.

[0049] With the foregoing in mind, FIGS. 6-12 illustrate use of the connector assembly 28 of FIGS. 2-5 with various types of casings systems. In particular, FIGS. 6 and 7 illustrate use of the connector assembly 28 of FIGS. 2-5 with a split compact casing system, FIGS. 8-10 illustrate use of the connector assembly 28 of FIGS. 2-5 with a mandrel casing system, and FIGS. 11 and 12 illustrate use of the connector assembly 28 of FIGS. 2-5 with a slip casing system.

[0050] FIG. 6 is cross-sectional side view of an embodiment of a portion of the wellhead 12 with the connector assembly 28, wherein the connector assembly 28 supports a split compact casing system 110. As shown, the connector assembly28 includes the lower spool 18, the upper spool 22, and the fastener 26 (which is one of multiple fasteners 26 distributed about the circumferential axis 38). The connector assembly 28 may also be considered to include or couple to a first casing 112 (e.g., intermediate casing).

[0051] In operation, the connector assembly 28 with the first casing 112 may be lowered and landed on a pack-off ring 114 that is coupled to a conductor 116 (e.g., conductor casing). For example, the connector assembly 28 may be lowered until a surface (e.g., axially-facing surface) contacts a shoulder (e.g., axially-facing shoulder) to form a landed interface 118. Then, a casing hanger 120 (e.g., a type of the casing hanger 20 of FIG. 1; part of the split compact casing system 110) may be lowered and landed within the connector assembly 28 (e.g., with or without rotation). In particular, the casing hanger 120 may be lowered until a surface contacts one of the protrusions 58 of the lower spool 18 to form a landed interface 122.

[0052] The casing hanger 120 may support a second casing 124 (e.g., inner casing). Once the casing hanger 120 is landed within the connector assembly 28, cementing operations may be completed to cement the casing hanger 120 within the wellbore 16 of FIG. 1. For example, cement returns may be routed axially across the casing hanger 120 through one or more openings 126 of the casing hanger 120, although present embodiments may utilize any of a variety of cement return pathways.

[0053] After the cementing operations, a casing seal assembly 128 may be installed between the casing hanger 120 and the connector assembly 28. For example, the casing seal assembly 128 may include a seal ring 130 (e.g., annular seal ring) that supports one or more seal elements 132 (e.g., annular seal elements). The casing seal assembly 128 may also include a push ring 134 (e.g., annular push ring) and a lock ring 136 (e.g., c-shaped ring or segmented ring). In FIG. 6, the seal ring 130 with the one or more seal elements, as well as the push ring 134 and the lock ring 136 may be run together via a running tool (not shown). At least a portion of the seal ring 130 may insert into a space (e.g.,annular space) between the casing hanger 120 and the connector assembly 28. Then, manipulation of the push ring 134 (e.g., via the tool; axial movement and / or rotation) may cause the push ring 134 to drive the lock ring 136 radially outwardly to engage the connector assembly 28. In particular, the lock ring 136 may engage one of the one or more grooves 62 of the upper spool 2 to lock the seal ring 130 within the connector assembly 28. It should be appreciated that the seal ring 130, the push ring 134, and the lock ring 136 may have any of a variety of configurations and may be installed via axial force (e.g., without rotation), rotation (e.g., with threaded interfaces), and / or any combination thereof.

[0054] FIG. 7 is cross-sectional side view of an embodiment of a portion of the wellhead 12 of FIG. 6, wherein the connector assembly 28 supports the split compact casing system 110 and the tubing hanger 24. As shown, the connector assembly 28 includes the lower spool 18, the upper spool 22, and the fastener 26 (which is one of multiple fasteners 26 distributed about the circumferential axis 38). The connector assembly 28 may also be considered to include or couple to the first casing 112. Additionally, as shown, the split compact casing system 110 includes the casing hanger 120 that supports the second casing 124. The split compact casing system 110 also includes the seal ring 130, the one or more seal elements 132, the push ring 134, and the lock ring 136.

[0055] In operation, the tubing hanger 24 may be lowered and landed within the connector assembly 28. In particular, the tubing hanger 24 may be lowered until a surface contacts a shoulder (e.g., which may be provided by the push ring 134 and / or the upper spool 22) to form a landed interface(s) 138. For example, the shoulder may be formed by one of the one or more grooves 62 or other surface features along the respective radially inner surface 54 of the upper spool 22. In certain embodiments, a tubing hanger lock ring 140 (e.g., c-shaped ring; segmented ring) may be driven (e.g., via a push ring 142 (e.g., annular ring)) to engage one of the one or more grooves 62 along the respective radially inner surface 54 of the upper spool 22.

[0056] The tubing hanger 24 may support tubing 144 and / or any of a variety of other equipment (e.g., control lines) that are suspended through the second casing 124. With the split compact casing system 110, the casing hanger 120 may be landed and the seal ring 130 may be placed and locked via tools that extend through the BOP stack (e.g., of the pressure control equipment 30 of FIG.1). As such, the split compact casing system 110 may be installed without removal of the BOP stack. However, the connector assembly 28 may be adjusted from the engaged configuration of FIGS. 6 and 7 to the disengaged configuration (e.g., the upper spool 22 may be separated from the lower spool 18, such as by loosening the multiple fasteners 26 and applying force in the axial direction 34 to lift the upper spool 22). For example, even if access to the split compact casing system 110 may not be utilized during successful installation (e.g., typical installation; without maintenance events) of the split compact casing system 110, the connector assembly 28 may enable access to the split compact casing system 110 during maintenance events (e.g., for inspection, repairs, and so forth). For example, if the second casing 124 were to become stuck during installation of the second casing 124, the connector assembly 28 may be adjusted from the engaged configuration to the disengaged configuration to provide access to the split compact casing system 110 for maintenance (e.g., a tool may be inserted in the radial direction 36 between the lower spool 18 and the upper spool 22 along the axial axis 34).

[0057] FIG. 8 is cross-sectional side view of an embodiment of a portion of the wellhead 12 with the connector assembly 28, wherein the connector assembly 28 supports a mandrel casing system 150. As shown, the connector assembly 28 includes the lower spool 18, the upper spool 22, and the fastener 26 (which is one of multiple fasteners 26 distributed about the circumferential axis 38). The connector assembly 28 may also be considered to include or couple to the first casing 112.

[0058] In operation, the connector assembly 28 with the first casing 112 may be lowered and landed on the pack-off ring 114 that is coupled to the conductor 116. Then, a casing hanger 152 (e.g., a type of the casing hanger 20 of FIG. 1;part of the mandrel casing system 150) may be lowered and landed within the connector assembly 28 (e.g., with or without rotation). In particular, the casing hanger 152 may be lowered until a surface contacts one of the protrusions 58 of the lower spool 18 to form a landed interface 154.

[0059] The casing hanger 152 may support a second casing 156 (e.g., inner casing; threaded onto the casing hanger 152). Once the casing hanger 152 is landed within the connector assembly 28, cementing operations may be completed to cement the casing hanger 152 within the wellbore 16 of FIG. 1. For example, cement returns may be routed axially across the casing hanger 152 through one or more openings 158 of the casing hanger 152, although present embodiments may utilize any of a variety of cement return pathways. After the cementing operations, the connector assembly 28 may be adjusted from an engaged configuration of FIG. 8 to a disengaged configuration of FIG. 9.

[0060] FIG. 9 is cross-sectional side view of an embodiment of a portion of the wellhead 12, wherein the lower spool 18 and the upper spool 22 are separated from one another to facilitate installation of a respective seal assembly 160 for the mandrel casing system 150. As shown, the connector assembly 28 includes the lower spool 18, the upper spool 22, and the fastener 26 (which is one of multiple fasteners 26 distributed about the circumferential axis 38). The connector assembly 28 may also be considered to include or couple to the first casing 112. Additionally, as shown, the mandrel casing system 150 includes the casing hanger 152 that supports the second casing 156.

[0061] As shown in FIG. 9, the upper spool 22 and the BOP stack (e.g., part of the pressure control equipment 30 of FIG. 1) may be lifted and separated from the lower spool 18 to reach the disengaged configuration. With the connector assembly 28 in the disengaged configuration, the respective seal assembly 160 may be installed in any suitable manner (e.g., manually; by a human operator and / or a tool; by insertion in the radial direction 36 between the lower spool 18 and the upper spool 22 along the axial axis 34). As shown, the respective seal assembly 160 may be installed between the casing hanger 152 and theconnector assembly 28. It should be appreciated that the respective seal assembly 160 may have any of a variety of configurations and may be installed via axial force (e.g., without rotation), rotation (e.g., with threaded interfaces), and / or any combination thereof. For example, the respective seal assembly 160 may include a seal ring 162 (e.g., annular seal ring) that supports one or more seal elements 164 (e.g., annular seal elements) and a lock ring 166 (e.g., annular ring). After placement (e.g., setting) the seal ring 162 into a space (e.g., annular space) between the casing hanger 152 and the connector assembly 28, the upper spool 22 may be lowered and landed on the lower spool 18 (e.g., as described with respect to FIGS. 2 and 3). Then, the upper spool 22 and the lower spool 18 may be fastened via the multiple fasteners 26 (e.g., as described with respect to FIGS. 4 and 5, and as shown in FIG. 10).

[0062] FIG. 10 is cross-sectional side view of an embodiment of a portion of the wellhead 12, wherein the connector assembly 28 supports the mandrel casing system 150 and the tubing hanger 24. As shown, the connector assembly 28 includes the lower spool 18, the upper spool 22, and the fastener 26 (which is one of multiple fasteners 26 distributed about the circumferential axis 38). The connector assembly 28 may also be considered to include or couple to the first casing 112. Additionally, as shown, the mandrel casing system 150 includes the casing hanger 152 that supports the second casing 156.

[0063] After placement of the seal assembly 160 and adjustment of the connector assembly 28 to the engaged configuration of FIG. 10, the tubing hanger 24 may be lowered and landed within the connector assembly 28. In particular, the tubing hanger 24 may be lowered until the surface contacts the shoulder (e.g., which may be provided by the upper spool 22) to form the landed interface(s) 138. For example, the shoulder may be formed by one of the one or more grooves 62 or other surface features along the respective radially inner surface 54 of the upper spool 22. In certain embodiments, the tubing hanger lock ring 140 may be driven (e.g., via the push ring 142) to engage one of the one or more grooves 62 along the respective radially inner surface 54 of the upper spool 22.

[0064] The tubing hanger 24 may support tubing 144 and / or any of a variety of other equipment (e.g., control lines) that are suspended through the second casing 124. With the mandrel casing system 150, the casing hanger 152 may be landed, then the upper spool 22 and the BOP stack may be lifted from the lower spool 18, then the seal assembly 160 may be placed, and then the upper spool 22 and the BOP stack may be lowered back onto the lower spool 18. Further, when the upper spool 22 is lowered back onto the lower spool, then the upper spool 22 may engage the lock ring 166 and retain the seal assembly 160 against the casing hanger 152. As such, the mandrel casing system 150 may be installed with temporary removal of the BOP stack. Further, the connector assembly 28 may be adjusted from the engaged configuration to the disengaged configuration (e.g., the upper spool 22 may be separated from the lower spool 18, such as by loosening the multiple fasteners 26 and applying force in the axial direction 34 to the upper spool 22) during maintenance events (e.g., for inspection, repairs, and so forth).

[0065] FIG. 11 is cross-sectional side view of an embodiment of a portion of the wellhead 12 with the connector assembly 28, wherein the connector assembly 28 supports a slip casing system 170. In FIG. 11, the lower spool 18 and the upper spool 22 are separated from one another to facilitate installation of a slip assembly 172 and a respective seal assembly 174 for the slip casing system 170. For purposes of discussion herein, the slip assembly 172 may be considered to be a casing hanger (e.g., a type of the casing hanger 20 of FIG. 1 ; part of the slip casing system 170). As shown, the connector assembly 28 includes the lower spool 18, the upper spool 22, and the fastener 26 (which is one of multiple fasteners 26 distributed about the circumferential axis 38). The connector assembly 28 may also be considered to include or couple to the first casing 112.

[0066] In operation, the connector assembly 28 with the first casing 112 may be lowered and landed on the pack-off ring 114 that is coupled to the conductor 116. Then, a second casing 176 (e.g., inner casing) may be run and cemented within the wellbore 16 of FIG. 1. Thereafter, as shown in FIG. 11, the upperspool 22 and the BOP stack (e.g., part of the pressure control equipment 30 of FIG. 1) may be lifted and separated from the lower spool 18 to reach the disengaged configuration. With the connector assembly 28 in the disengaged configuration, the slip assembly 172 and the respective seal assembly 174 may be installed in any suitable manner (e.g., manually; by a human operator and / or a tool; by insertion in the radial direction 36 between the lower spool 18 and the upper spool 22 along the axial axis 34). For example, the second casing 176 may be cut via this external access (e.g., rather than via an internal cutter lowered through the upper spool 22). As shown, the slip assembly 172 and the respective seal assembly 174 may be placed (e.g., set) between the second casing 176 and the connector assembly 28. It should be appreciated that the slip assembly 172 and the respective seal assembly 160 may have any of a variety of configurations and may be installed via any suitable techniques, such as by applying axial force (e.g., without rotation).

[0067] As shown, the slip assembly 172 may include a slip body 178 and slip segments 180 (e.g., tapered and / or toothed segments). The slip assembly 172 may be lowered and landed within the connector assembly 28. In particular, the slip assembly 172 may be lowered until a surface contacts one of the protrusions 58 of the lower spool 18 to form a landed interface 182. The slip body 178 circumferentially surrounds the slip segments 180 and is configured to drive the slip segments 180 to engage (e.g., grip) the second casing 176, such as in response to the slip assembly 172 forming the landed interface 182. For example, at least one of the one or more protrusions 58 may contact and drive the slip body 178 radially inwardly, which may then drive the slip segments 180 radially inwardly to engage the second casing 176. In this way, the slip assembly 172 may hold the second casing 176 and block relative movement between the slip assembly 172 and the second casing 176.

[0068] As shown, the respective seal assembly 174 may include a seal ring 184 (e.g., annular seal ring) that supports one or more seal elements 186 (e.g., annular seal elements) and a lock ring 188 (e.g., annular ring; protrusion of the seal ring 184). After placement (e.g., setting) the seal assembly 184 into a space(e.g., annular space) between the second casing 176 and the connector assembly 28, the upper spool 22 may be lowered and landed on the lower spool 18 (e.g., as described with respect to FIGS. 2 and 3). Then, the upper spool 22 and the lower spool 18 may be fastened via the multiple fasteners 26 (e.g., as described with respect to FIGS. 4 and 5, and as shown in FIG. 12).

[0069] FIG. 12 is cross-sectional side view of an embodiment of a portion of the wellhead 12, wherein the connector assembly 28 supports the slip casing system 170 and the tubing hanger 24. As shown, the connector assembly 28 includes the lower spool 18, the upper spool 22, and the fastener 26 (which is one of multiple fasteners 26 distributed about the circumferential axis 38). The connector assembly 28 may also be considered to include or couple to the first casing 112. Additionally, as shown, the slip casing system 170 includes the slip assembly 172 that supports the second casing 176.

[0070] After placement of the slip assembly 172 and the seal assembly 174 and adjustment of the connector assembly 28 to the engaged configuration of FIG. 12, the tubing hanger 24 may be lowered and landed within the connector assembly 28. In particular, the tubing hanger 24 may be lowered until the surface contacts the shoulder (e.g., which may be provided by the seal assembly 174 and / or the upper spool 22) to form the landed interface(s) 138. For example, the shoulder may be formed by one of the one or more grooves 62 or other surface features along the respective radially inner surface 54 of the upper spool 22. In certain embodiments, the tubing hanger lock ring 140 may be driven (e.g., via the push ring 142) to engage one of the one or more grooves 62 along the respective radially inner surface 54 of the upper spool 22.

[0071] The tubing hanger 24 may support tubing 144 and / or any of a variety of other equipment (e.g., control lines) that are suspended through the second casing 124. With the slip casing system 170, the second casing 176 may be cemented, then the upper spool 22 and the BOP stack may be lifted from the lower spool 18, then the slip assembly 172 and the seal assembly 174 may be placed, and then the upper spool 22 and the BOP stack may be lowered backonto the lower spool 18. Further, when the upper spool 22 is lowered back onto the lower spool, then the upper spool 22 may engage the lock ring 188 and retain the seal assembly 174 against the slip assembly 172. As such, the slip casing system 170 may be installed with temporary removal of the BOP stack. Further, the connector assembly 28 may be adjusted from the engaged configuration to the disengaged configuration (e.g., the upper spool 22 may be separated from the lower spool 18, such as by loosening the multiple fasteners 26 and applying force in the axial direction 34 to the upper spool 22) during maintenance events (e.g., for inspection, repairs, and so forth).

[0072] As shown at least in FIGS. 6-8, 10, and 12, the connector assembly 28 includes features that enable the fasteners 26 to join the lower spool 18 and the upper spool 22 in a manner that provides an outer diameter (e.g., maximum outer diameter) for the connector assembly 28 that is less than an inner diameter of the BOP stack (e.g., of the pressure control equipment 30 of FIG. 1).

[0073] Additionally, as shown at least in part across FIGS. 1-12, the multiple recesses 64 and the multiple openings 72, 74 are angled (e.g., acute angle) relative to the axial axis 34 and the radial axis 36 and cause the fasteners 26 to be angled (e.g., acute angle) relative to the axial axis 34 and the radial axis 36 when the fasteners 26 are in place to couple the lower spool 18 and the upper spool 22 to one another. For example, a radially outer edge of a respective fastener 26 may be further from the wellbore 16 along the axial axis 34 as compared to a radially inner edge of the respective fastener 26. Thus, at least in certain embodiments, the fasteners 26 are not placed to extend along the axial axis 34 (e.g., axially or vertically; not parallel to the axial axis) and are not placed extend along the radial axis 36 (e.g., radially or horizontally; not parallel to the radial axis 36). While the fasteners 26 are shown to be angled about 30 degrees relative to the axial axis 34, it should be appreciated that the fasteners 26 may be at any suitable angle relative to the axial axis 34 (e.g., between about 15 to 75, 25 to 65, or 35 to 55 degrees). However, it should be noted that the fasteners 26 may be oriented axially, radially, and / or angled in another manner (e.g., a radially inner edge of a respective fastener 26 may be further from the wellbore 16 alongthe axial axis 34 as compared to a radially outer edge of the respective fastener 26; the multiple recesses 64 may be formed in the upper spool 22, such that the fasteners 26 insert through through-hole openings in the upper spool 22 and into blind hole, threaded openings in the lower spool 18. This may provide advantages including gravity-assisted tightening, while orientations shown in FIGS. 4-12 may provide advantages including relatively low debris buildup on the fasteners 26, for example.

[0074] Due to geometry of the lower spool 18 and the upper spool 22 as described herein, the fasteners 26 may fit within the multiple recesses 64 defined about the lower spool 18. Thus, at least in certain embodiments, the fasteners 26 may not extend radially outward beyond the radially outer surface of the connector assembly 28. As described herein, the multiple recesses 64 may be distributed circumferentially about the lower spool 18 to receive the fasteners 26 at spaced apart locations circumferentially about the lower spool 18. In certain embodiments, the multiple recesses 64 may be spaced evenly about the lower spool 18 with one fastener 26 per recess 64. However, it should be appreciated that any suitable arrangement and / or or number of recesses 64, as well as fasteners 26 per recess 64, may be provided in the connector assembly 28 (e.g., uneven spacing; multiple fasteners 26 per recess 64; one recess 64 for all of the multiple fasteners 26).

[0075] Additionally, the respective inner surface 50 of the lower spool 18 and / or the respective inner surface 54 of the upper spool 22 may include features that support use of the connector assembly 28 with the various types of casing systems. For example, in certain embodiments, the respective inner surfaces 50, 54 may include first features (e.g., first combination of features; first internal profile) utilized by a first type of casing system (e.g., and not by a second type of casing system and / or a third type of casing system), second features (e.g., second combination of features; second internal profile) utilized by the second type of casing system (e.g., and not by the first type of casing system and / or the third type of casing system), third features (e.g., third combination of features; third internal profile) utilized by the third type of casing system (e.g., and not bythe first type of casing system and / or the second type of casing system), and so forth. For example, with reference to FIGS. 6 and 7, the groove 62 may receive the lock ring 136 for retention of the seal assembly 128. However, with reference to FIGS. 10 and 12, the groove 62 is not utilized by the mandrel casing system 150 or the slip casing system 170.

[0076] It should also be appreciated that certain features may be shared by one or more of the various types of casing systems (e.g., the first features are utilized by the first type of casing system and the second type of casing system, but not the third type of casing system). For example, with reference to FIGS. 9 and 10, the upper spool 22 may include a surface 190 (e.g., locking feature) that contacts the lock ring 166 for retention of the respective seal assembly 160. Further, with reference to FIG. 12, the upper spool 22 may include the surface 190 that contacts the lock ring 188 for retention of the respective seal assembly 174. However, with reference to FIGS. 6 and 7, the surface of the upper spool 22 is not utilized by the split compact casing system 110, and instead the lock ring 136 is utilized for retention of the seal assembly 128. As another example, with reference to FIGS. 6, 9, and 11, the lower spool 18 may include the protrusion 58 (e.g., a same protrusion 58) that supports the casing hanger 120, the casing hanger 152, and the slip assembly 172.

[0077] As such, in certain embodiments, the respective inner surfaces 50, 54 may provide dedicated features, type-specific features, and / or multiple features that can be utilized in different ways (e.g., different combinations) to provide different internal profiles suitable for the various types of casing systems. As a result, some features may be utilized (e.g., landed on; contacted) and some other features may not be utilized (e.g., not landed on; not contacted) for a particular type of casing system installed within the connector assembly 28. Thus, for at least for one type of casing system that is suitable for installation within the connector assembly 28, there may be at least one feature of the respective inner surfaces 50, 54 that is not utilized in that installation configuration.

[0078] FIG. 13 is a flow diagram of an embodiment of a method 200 of operating a connector assembly (e.g., the connector assembly 28 of FIGS. 1-12). The method 200 disclosed herein includes various steps represented by blocks. Although the method 200 illustrates the blocks in a certain sequence, it should be understood that the blocks may be performed in any suitable order, certain blocks may be performed simultaneously, certain blocks may be omitted, and / or additional blocks may be added. For example, the method 200 includes block 202 prior to blocks 204, 206, 208, and 210 to emphasize that the connector assembly may be utilized with various types of casing systems. However, in operation, it is likely that an operator would complete one or more of blocks 204, 206, 208, or 210 prior to block 202 (i.e. , it is likely that the operator would make a decision regarding a type of casing system to employ at a wellsite prior to carrying out steps to land the connector assembly as part of a wellhead). In certain embodiments, a kit of the connector assembly and respective components one or more different types of casing systems may be provided to the operator and / or a wellsite (e.g., offered as a packaged; offered as complementary equipment; packaged separately or together) to enable the operator to assess the wellsite and make the decision regarding the type of casing system to employ at the wellsite and then be prepared to proceed with any decision in advance.

[0079] In block 202, the method 200 may include landing a connector assembly as part of a wellhead. The connector assembly may include a lower spool and an upper spool that are coupled to one another via fasteners, and the connector assembly may be sized to fit through a BOP stack.

[0080] In blocks 204, 206, and 208, the method 200 may include determining a type of casing system to utilize with the connector assembly. In particular, in block 204, the method 200 may include determining whether to utilize a split compact casing system. In block 206, the method 200 may include determining whether to utilize a mandrel casing system. In block 208, the method 200 may include determining whether to use a slip casing system. Upon determining not to proceed with the split compact casing system, the mandrel casing system, orthe slip casing system, then the method 200 may include proceeding with another suitable type of casing system at block 210.

[0081] However, upon determining to proceed with the split compact casing system, the method 200 may proceed to multiple blocks to install the split compact casing system. In block 212, the method 200 may include landing a casing hanger in the lower spool. The casing hanger may support a casing. In block 214, the method 200 may include completing cementing operations to cement the casing within a wellbore. In block 216, the method 200 may include installing and locking a seal assembly to thereby form an annular seal between the casing hanger and the connector assembly. In block 218, the method 200 may include landing a tubing hanger in the upper spool. In this way, blocks 212-218 may enable installing the split compact casing system with the connector assembly, such as without separation of the upper spool from the lower spool. In this way, the split compact casing system may be installed without separation of the upper spool and a BOP stack from the lower spool. However, in response to maintenance events, the upper spool and the BOP stack may be separated from the lower spool to provide access at a location axially between the upper spool and the lower spool, for example.

[0082] Further, upon determining to proceed with the mandrel casing system, the method 200 may proceed to multiple blocks to install the split compact casing system. In block 222, the method 200 may include landing a casing hanger in the lower spool. The casing hanger may support a casing. In block 224, the method 200 may include completing cementing operations to cement the casing within a wellbore. In block 226, the method 200 may include separating the upper spool from the lower spool, such as to provide access at a location axially between the upper spool and the lower spool, for example. In block 228, the method 200 may include installing (e.g., manually) a seal assembly to thereby form an annular seal between the casing hanger and the connector assembly. In block 230, the method 200 may include reconnecting the upper spool and the lower spool. In block 218, the method 200 may include landing the tubing hanger in the upper spool. In this way, blocks 222-230 and 218 may enable installingthe mandrel casing system with the connector assembly, such as with planned separation of the upper spool from the lower spool to facilitate installation of the seal assembly. Further, in response to maintenance events, the upper spool and the BOP stack may be separated from the lower spool to provide access at a location axially between the upper spool and the lower spool, for example.

[0083] Further, upon determining to proceed with the slip casing system, the method 200 may proceed to multiple blocks to install the slip casing system. In block 242, the method 200 may include running and cementing casing within the wellbore. In block 244, the method 200 may include separating the upper spool from the lower spool, such as to provide access at a location axially between the upper spool and the lower spool, for example. In block 246, the method 200 may include installing (e.g., manually) a slip assembly to engage the casing. When installed, the slip assembly may operate as and / or be considered to be a casing hanger. In block 248, the method 200 may include installing (e.g., manually) a seal assembly to thereby form an annular seal between the casing and the connector assembly. In block 250, the method 200 may include reconnecting the upper spool and the lower spool. In block 218, the method 200 may include landing the tubing hanger in the upper spool. In this way, blocks 242-250 and 218 may enable installing the slip casing system with the connector assembly, such as with planned separation of the upper spool from the lower spool to facilitate installation of the seal assembly. Further, in response to maintenance events, the upper spool and the BOP stack may be separated from the lower spool to provide access at a location axially between the upper spool and the lower spool, for example.

[0084] Although not shown in FIG. 13, it should be appreciated that the method 200 may include determining occurrence of an event (e.g., the casing is stuck in the wellbore). In response to determining no occurrence of an event, the method 200 may proceed as shown. However, in response to determining occurrence of an event (e.g., the casing is stuck in the wellbore), the method 200 include removing multiple fasteners to separate the upper spool from the lower spool (e.g., adjusting the connector assembly from an engaged configuration to adisengaged configuration). For example, an operator may remove (e.g., unthread, loosen, and / or withdraw) the multiple fasteners and then separate (e.g., lift, move) the upper spool of the connector assembly from the lower spool of the connector assembly to gain access to equipment within the connector assembly and / or the wellbore (e.g., without running a tool through the BOP stack and the connector assembly).

[0085] While the disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims. For example, while the illustrated embodiments show a hanger and a housing of a wellhead, it should be understood that the systems and methods may be adapted to for use with any of a variety of other annular structures. Additionally, any features shown or described with reference to FIGS. 1-13 may be combined in any suitable manner.

[0086] The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function]...” or “step for [performing [a function]...”, it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Claims

CLAIMS1. A connector assembly for a wellhead, the connector assembly comprising:a lower spool with a first radially-inner surface;an upper spool with a second radially-inner surface; anda plurality of fasteners configured to couple the lower spool and the upper spool to one another with an outer diameter that enables the connector assembly to fit through a blowout preventer (BOP) stack;wherein the first radially-inner surface, the second radially-inner surface, or both include first features configured to support a first type of casing system in the connector assembly and second features configured to support a second type of casing system in the connector assembly.

2. The connector assembly of claim 1, wherein the plurality of fasteners are configured to be entirely within the outer diameter of the connector assembly while the plurality of fasteners couple the lower spool and the upper spool to one another.

3. The connector assembly of claim 1, wherein the first features and the second features comprise a shoulder configured to support a hanger with a casing.

4. The connector assembly of claim 1, wherein the first features comprise a groove configured to receive a lock ring that is driven radially outwardly by a push ring of the first type of casing system to support the first type of casing system in the connector assembly.

5. The connector assembly of claim 4, wherein the second features comprise a surface configured to engage a lock ring that extends radially outwardly from aseal assembly of the second type of casing system to support the second type of casing system in the connector assembly.

6. The connector assembly of claim 1 , wherein the first type of casing system and the second type of casing system comprise at least two of a split compact casing system, a mandrel casing system, or a slip casing system.

7. The connector assembly of claim 1 , wherein the first radially-inner surface, the second radially-inner surface, or both include third features configured to support a third type of casing system in the connector assembly.

8. The connector assembly of claim 1, comprising a plurality of recesses distributed circumferentially about the lower spool, wherein each recess of the plurality of recesses is configured to receive a respective fastener of the plurality of fasteners.

9. The connector assembly of claim 1, wherein the lower spool comprises a plurality of through-holes, the upper spool comprises a plurality of blind holes, and each through-hole of the plurality of through-holes is aligned with one blind hole of the plurality of blind holes to receive a respective fastener of the plurality of fasteners.

10. The connector assembly of claim 9, wherein the plurality of through-holes are devoid of threads, and the plurality of blind holes comprise threads.

11. The connector assembly of claim 9, wherein a respective diameter of each through-hole of the plurality of through-holes is greater than a respective diameter of each blind hole of the plurality of blind holes, such that a gap is provided between a respective fastener of the plurality of fasteners and a respective through-hole of the plurality of through-holes prior to threading the respective fastener within a respective blind hole of the plurality of blind holes.

12. A wellhead system, comprising:a lower spool comprising a plurality of first openings;an upper spool comprising a plurality of second openings; anda plurality of fasteners, wherein each fastener of the plurality of fasteners is configured to insert through a respective first opening of the plurality of first openings and thread into a respective second opening of the plurality of second openings to couple the lower spool and the upper spool to one another to form a connector assembly with an outer diameter that enables the connector assembly to fit through a blowout preventer (BOP) stack;wherein the lower spool, the upper spool, or both include first features configured to support a first type of casing system in the connector assembly and second features configured to support a second type of casing system in the connector assembly.

13. The wellhead system of claim 12, wherein each fastener of the plurality of fasteners is positioned at an acute angle relative to an axial axis while the plurality of fasteners couple the lower spool and the upper spool to one another.

14. The wellhead system of claim 12, wherein the first type of casing system is configured to be installed without lifting the BOP stack, and the second type of casing system is configured to be installed with lifting the BOP stack.

15. The wellhead system of claim 12, comprising a kit with the connector assembly, respective components of the first type of casing system, and respective components of the second type of casing system.

16. The wellhead system of claim 12, comprising a plurality of alignment pins and an annular seal element at a stepped interface between the lower spool and the upper spool.

17. A method, comprising:landing a connector assembly on one or more additional housing portions to form a wellhead housing, wherein the connector assembly comprises a lower spool, an upper spool, and a plurality of fasteners that couple the lower spool and the upper spool to one another with an outer diameter that enables the connector assembly to fit through a blowout preventer (BOP) stack;running a casing hanger that supports a casing to land on a shoulder of the lower spool; andplacing a seal assembly that provides a seal for the casing hanger, wherein placing the seal assembly comprises utilizing a first locking feature of the upper spool to lock the seal assembly within the connector assembly without utilizing a second locking feature of the upper spool.

18. The method of claim 17, comprising selecting the casing hanger from a plurality of types of casing hangers that are suitable for use with the connector assembly, wherein at least one of the plurality of types of casing hangers is configured to utilize the second locking feature of the upper spool.

19. The method of claim 17, comprising lifting the upper spool and the BOP stack after cementing the casing to provide an axial space between the lower spool and the upper spool, and placing the seal assembly by inserting the seal assembly in a radial direction through the axial space between the lower spool and the upper spool.

20. The method of claim 17, comprising, in response to identifying occurrence of an event, loosening the plurality of fasteners to separate the upper spool from the lower spool.

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