A multi-component C-ring coupling is provided that includes a connector, an internal C-ring, and a lower ring. In one embodiment, the multi-component C-ring coupling may include a diverter connector to weldlessly couple a diverter to a pipe, such as a conductor. In other embodiment, the coupling may include a casing housinghead connector to couple to a casing housinghead. The lower ring may be engaged with the connector via axial fasteners. The lower ring and connector may include angled internal surfaces to exert radial forces on the C-ring and cause engagement of the teeth of the C-ring with the outer wall of a pipe.

BACKGROUND

As will be appreciated, oil and natural gas have a profound effect on modern economies and societies. Indeed, devices and systems that depend on oil and natural gas are ubiquitous. For instance, oil and natural gas are used for fuel in a wide variety of vehicles, such as cars, airplanes, boats, and the like. Further, oil and natural gas are frequently used to heat homes during winter, to generate electricity, and to manufacture an astonishing array of everyday products.

In order to meet the demand for such natural resources, companies often invest significant amounts of time and money in searching for and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired resource is discovered below the surface of the earth, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a wellhead assembly through which the resource is extracted. These wellhead assemblies may include a wide variety of components, such as various casings, valves, fluid conduits, and the like, that control drilling and/or extraction operations.

Couplings (also referred to as connectors) are employed to attach certain components together and to wellhead housings. During drilling and construction of the well, coupling techniques may include welding or machining the components and/or the connector, such as by welding two components together, machining threads or other fastening mechanism into the component and/or connector.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Embodiments of the present invention include a multi-component C-ring coupling having a removably coupling lower ring to enable easier removal and inspection of the coupling. Additionally, the coupling may provide attachment of a diverter or riser to a pipe (such as a conductor) without welding. In one embodiment, the multi-component C-ring connector includes a sliplock connector, such as for a diverter or a casing housinghead, a lower ring, and an internal C-ring. The lower ring may be removably coupled to the connector via axial fasteners or a threaded connection. The lower ring may be axially translated until it engages the C-ring. The lower ring and connector include internal angled surfaces such that when the lower ring is engaged the lower ring and connector exert axial and radial forces on the internal C-ring. The resulting radial force pushes teeth of the C-ring radially inward to cause the teeth to bite a pipe. In other embodiments, the connector may include radial fasteners inserted into the connector to engage the internal C-ring.

FIGS. 1A and 1Bare a block diagrams that illustrates an embodiment of a mineral extraction system10. As discussed below, one or more tubular couplings are employed throughout the system10. The illustrated mineral extraction system10can be configured to extract various minerals and natural resources, including hydrocarbons (e.g., oil and/or natural gas), or configured to inject substances into the earth. In some embodiments, the mineral extraction system10is land-based (e.g., a surface system) or subsea (e.g., a subsea system). As illustrated, the system10includes a wellhead assembly12coupled to a mineral deposit14via a well16, wherein the well16includes a wellhead hub18and a well-bore20. The wellhead hub18generally includes a large diameter hub that is disposed at the termination of the well-bore20. The wellhead hub18provides for the sealable connection of the wellhead assembly12to the well16.

The wellhead assembly12typically includes multiple components that control and regulate activities and conditions associated with the well16. For example, the wellhead assembly12generally includes pipes, bodies, valves and seals that enable drilling of the well16, route produced minerals from the mineral deposit14, provide for regulating pressure in the well16, and provide for the injection of chemicals into the well-bore20(down-hole). For example,FIG. 1Aillustrates a conductor22(also referred to as “conductor casing”) disposed in the well20to provide structure for well and prevent collapse of the sides of the well26into the well-bore20. One or more casings24, such as surface casing, intermediate casing, etc., may be fully or partially disposed in the bore of the conductor22. The casing24also provides a structure for the well16and well-bore20and provides for control of fluid and pressure during drilling of the well16.

During various stages of drilling of the well16, a diverter26(or a riser or other pipe) may be coupled to the conductor22via the multi-component C-ring coupling28. The diverter26(also referred to as a type of blowout preventer (BOP). The diverter26may include a variety of valves, fittings and controls to prevent oil, gas, or other fluid from exiting the well in the event of an unintentional release of pressure or an unanticipated overpressure condition. The diverter26may be mechanically or hydraulically operated and may allow diversion of fluids flowing from the well16away from rig or other equipment via side outlets30. During operation of the system10, it may be typical to install a diverter26during removal or installation of additional components, changes in operation of the system10, or for other safety reasons. As described further below, the multi-component C-ring coupling28enables secure coupling of the diverter26to the conductor22without welding.

FIG. 1Bdepicts another operation of the wellhead assembly12illustrating installation of additional casing24, such as additional surface casing, intermediate casing, or production casing, to the wellhead assembly12. To install additional casing, a casing housinghead32may be coupled to the casing24via the multi-component C-ring coupling28. Again, as described further below, the multi-component C-ring coupling28enables coupling of the casing housinghead32to the casing24without welding. The casing housinghead32may provide for installation of additional components, such as a BOP or a casing spool34. The casing spool34may provide for installation of additional casing, such as through use of a casing hanger installed inside the casing spool34.

FIG. 2depicts a cross-section of the multi-component C-ring coupling28coupled to a portion of a pipe38, such as the conductor22, the casing24, or any other pipe. The multi-component C-ring coupling28includes a converter connector40, a lower ring42, and an internal C-ring44. For example, the connector40may couple to the pipe38by one or more seals42. The connector40includes an internal angled surface41and the lower ring includes an internal angled surface43generally angularly opposed to the internal angled surface41, such that the surfaces41and43generate equal radial forces between the surfaces41and43and the internal C-ring44.

In the embodiment depicts inFIG. 2, the lower ring42may be removably coupled to the connector40via one or more axial fasteners46inserted into receptacles48of the lower ring42. The axial fasteners46may insert through the receptacles48and into a recess50of the connector40. In some embodiments, the receptacles48, the recesses50, the fasteners46, or any combination thereof may be threaded to facilitate engagement between the receptacles48, the recesses50, and the fasteners46. In certain embodiments, the fasteners46may be bolts, screws, or any suitable fastener.

The internal C-ring44includes teeth52that extend radially inward toward the pipe38. The teeth52extend to and bite the outer wall54of the pipe38to secure the coupling28to the pipe38. As described in detail below, the teeth52of the internal C-ring44are radially engaged via the axial and generally uniform radial force applied by the axial compression between the lower ring42and connector40.

To engage the coupling28, the lower ring42may by moved in the axial direction, indicated by arrow56, by engaging the axial fasteners46into the connector40, reducing the axial gap58between the connector40and the lower ring42. The fasteners46may be tightened in an alternating cross-pattern to the desired torque. In certain embodiments, the coupling28may include between approximately 1 to 50, 2 to 40, 3 to 30, 4 to 20, or 5 to 10 fasteners 46 equally spaced about a circumference of the coupling28.

As the lower ring42moves in the axial direction indicated by arrow56, the internal angled surface43comes into contact with the internal C-ring44, exerting axial and radial forces on the internal C-ring44, as indicated by arrow60. Similarly, as the gap58reduces, the internal angled surface41of the connector40exerts opposite radial and axial forces on the internal C-ring44, as indicated by arrow62. The combination of the forces indicated by arrows60and62results in a generally uniform radial force (indicated by arrow64) on the internal C-ring44due to the angled surfaces41and43engaging the internal C-ring44. This radial force indicated by arrow64forces the teeth52radially inward to bite into the outer wall54of the pipe38. An operator may visually verify the status of the internal C-ring through the gap58to ensure the teeth52of the C-ring44fully bit the pipe38.

The angle of the surfaces41and43may be designed for engagement with the internal C-ring44and/or for the desired radial force on the C-ring44. In some embodiments, the internal angled surface41and/or the internal angled surface43may be angled at least less than approximately 90° relative to a central axis of the tubing, e.g., approximately 10°, 20°, 30°, 40°, 45°, 50°, 60°, 70°, 80°, etc. For example, in certain embodiments, the internal angled surface41and/or the internal angled surface43may be angled between approximately 30 to 60°, between approximately 40 to 50°, or approximately 45°. Moreover, the internal angled surface41and the internal angled surface43may have the same or different angles from one another.

Additionally, the multi-component C-ring coupling28provides the ability to verify the status of the internal C-ring44without removal or disassembly of the coupling28. After installation, the gap58between the connector40and the lower ring42may be maintained, allowing visible verification of the internal C-ring44. For example, the thickness of the internal C-ring44may provide for the gap58up to a specific torque on the fasteners26. An operator may view the status of the internal C-ring44by looking through the gap58, as indicated by arrow66. In this manner, the integrity of the internal C-ring44may be verified without removal or disassembly of the coupling28.

Additionally, removal of the multi-component C-ring coupling28may be easier and safer than conventional couplings. To remove the multi-component C-ring coupling28, the lower ring42may be removed by removing the axial fasteners46from the connector40. The removability of the lower ring42enables an operator to view and easily remove the axial and radial forces (indicated by arrow62) applied to the internal C-ring44and, thus, easily remove or reduce the radial force (indicated by arrow64) engaging the teeth52of the internal C-ring44with the outer wall of the pipe38.

FIG. 3is a cross-section of the casing housinghead32coupled to a pipe38via the multi-component C-ring coupling28in accordance with an embodiment of the present invention. In the embodiment depicted inFIG. 3, the casing housinghead32may be coupled to a casing housinghead connector68of the multi-component C-ring coupling28via the one or more flanges70. The flanges70may include fasteners72to couple to the casing housinghead32via recesses74. The flanges70may also include fasteners76to couple to the connector68via recesses78. In the embodiment depicted inFIG. 3, the connector68may include annular seals80, such as O-rings, to seal and secure the connector40to the outer wall54of the pipe38.

In certain embodiments, the connector68may be an existing connector for the casing housinghead32. In such an embodiment, recesses50may be machined or otherwise formed in the connector68to receive the fasteners46. As shown inFIG. 3and as described above, to secure the coupling28to the pipe38the lower ring42may be axially moved via the engagement of fasteners46to reduce the gap58and apply axial and radial force to the internal C-ring44(as indicated by arrows60and62). Additionally, in some embodiments the connector68may include one or more test ports80to test the integrity of the annular seals80. Further, the cost of the housinghead32may be reduced by using a standard forging for the housinghead32.

FIG. 4is an alternate embodiment of the multi-component C-ring coupling28having a threaded connection82between the lower ring42and the diverter connector40. As shown inFIG. 4, the coupling28does not include any fasteners in the lower ring42and the connector40. Instead, the lower ring42includes internal threads84. The connector40may include external threads86configured to couple to the internal thread84of the lower ring42. To engage the lower ring42, the lower ring42may be threaded onto the threaded connection82and rotated to cause axial movement (indicated by arrow56) to engage the lower ring42and connection40with the internal C-ring44. The threaded connection82between the lower ring42and the connection40provides the same advantages discussed above with regard to the embodiments depicted inFIGS. 2 and 3. That is, the lower ring42may be axially translated until the axial forces (depicted by arrows60and62) exert on the internal C-ring44, causing a generally uniform radial inward force (indicated by arrow64) to cause the teeth52to bite the outer wall54of the pipe38. Similarly, to release or remove the coupling28, the lower ring42may be disengaged from the threaded connection82, removing or reducing the axial and radial force on the internal C-ring44.

FIG. 5depicts an alternate embodiment of the multi-component C-ring28having one or more radial fasteners87and a threaded connection88. The lower ring42may be removably coupled to the connector40via the threaded connection88. In the embodiment depicted inFIG. 5, the connector40includes an extended portion90that extends fully or partially over the lower ring42. The extended portion90includes internal threads92, and the lower ring42includes external threads94configured to engage with the internal threads92and form threaded connection88.

As shown inFIG. 5, the connector40does not include the internal angled surface41. Instead, the connector40includes one or more receptacles96disposed above the lower ring42. The radial fasteners87may be inserted radially into the receptacles96to engage the internal C-ring44. In such embodiment, the fasteners87and the receptacles96may be threaded to facilitate engagement between the fasteners87and the receptacles96. The radial fasteners87include an angled surface98(e.g., a conical tip portion) angularly opposed to the angled surface43of the lower ring42. In such an embodiment, the angled surface98of the fasteners87exerts an axial force on the internal C-ring44(indicated by arrow62) when the fastener87is engaged.

The coupling28ofFIG. 5may be installed by first inserting the fasteners87, and then engaging the lower ring42to the connector40via the threaded connection88. The lower ring42may be axially translated along the threaded connection88until the lower ring42engages the internal C-ring44. Alternatively, the coupling28may be installed by first engaging the lower ring42onto the threaded connection88, and subsequently inserting the fasteners87. To remove the coupling28depicted inFIG. 5, the lower ring42may be first removed and then the fasteners87may be subsequently removed. Alternatively, the fasteners87may be first removed and then the lower ring42may be subsequently removed.

Although the embodiment above discuss a diverter, riser, or casing housinghead, it should be appreciated that the multi-component C-ring coupling may be used to couple any wellhead component to a pipe, such as a conductor, casing, etc. The connector of the coupling may be modified for engagement with any such wellhead component.