Patent Application
20170183932
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. 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 embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In order to meet consumer and industrial demand for natural resources, companies often invest significant amounts of time and money in finding and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired subterranean resource such as oil or natural gas is discovered, 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 mounted on a well through which the resource is accessed or extracted. These wellhead assemblies may include a wide variety of components, such as casings, hangers, packoffs, valves, pumps, fluid conduits, and the like, that facilitate drilling or production operations. As will be appreciated, various tubular strings can be run into wells through wellhead assemblies. For instance, wells are often lined with casing that generally serves to stabilize the well and to isolate fluids within the wellbore from certain formations penetrated by the well (e.g., to prevent contamination of freshwater reservoirs). Wells can also include tubing strings that facilitate flow of fluids through the wells. Hangers can be attached to the casing and tubing strings and be received within wellheads to enable these tubular strings to be suspended in the wells from the hangers. Additional components, such as blowout preventers and production trees, can also be mounted on wellheads during drilling or production operations.
Certain aspects of some embodiments disclosed herein are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.
Embodiments of the present disclosure generally relate to wellhead assemblies mounted over wells. In at least some embodiments, a wellhead assembly includes a wellhead housing having an upper end with a recessed pocket. A drilling adapter can be received in the pocket for drilling operations. The wellhead can be converted for production by removing the drilling adapter, installing a sealing wafer in the pocket, and attaching another component to the wellhead housing over the sealing wafer. In some instances, the drilling adapter is secured to the wellhead housing with a collar threaded onto a threaded surface of the wellhead housing, and a threaded flange is spun onto the threaded surface after removing the drilling adapter and collar to allow a flanged connection with another component. Further, elastomeric seals can be used to seal the drilling adapter to the wellhead housing, while metal seals can be used with the sealing wafer to seal the connection of the wellhead housing to a different component. In at least one such embodiment, the pocket of the wellhead housing, the sealing wafer, and the lower end of the drilling adapter enable the wellhead apparatus to convert between elastomeric sealing between the wellhead housing and the drilling adapter for a drilling phase and metal-to-metal sealing between the wafer, the wellhead housing, and an additional component for a production phase.
Various refinements of the features noted above may exist in relation to various aspects of the present embodiments. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of some embodiments without limitation to the claimed subject matter.
These and other features, aspects, and advantages of certain embodiments will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Specific embodiments of the present disclosure are described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be 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.
When introducing elements of various embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, any use of “top,” “bottom,” “above,” “below,” other directional terms, and variations of these terms is made for convenience, but does not require any particular orientation of the components.
Turning now to the present figures, a system 10 is illustrated in
The wellhead hangers 22 can be positioned on landing shoulders within hollow wellhead bodies (e.g., within the tubing and casing heads). These landing shoulders can be integral parts of tubing and casing heads or can be provided by other components, such as sealing assemblies or landing rings disposed in the tubing and casing heads. Each of the hangers 22 can be connected to a tubular string, such as a tubing string 26 or a casing string 28, to suspend the string within the well 14. The well 14 can include a single casing string 28 or include multiple casing strings 28 of different diameters, and these casing strings 28 are often cemented in place within the well.
Additional equipment can be mounted on a wellhead at the well 14. For example, the depicted system 10 includes a tree 24 (e.g., a production tree), which can be mounted on the wellhead to facilitate resource production from the reservoir 12 via the well 14. It will be appreciated that the well 14 can be drilled through the wellhead, such as by a rotating drill string extending into the earth through the casing head 18. During such drilling operations, other devices (e.g., a blowout preventer) may be mounted on the wellhead in place of the tree 24. The wellhead assembly can be converted from a drilling phase to a production phase by removing the blowout preventer (or other devices) and mounting the tree 24 on the wellhead. Moreover, in at least certain embodiments of the present disclosure a hybrid connection technique can be used for connecting equipment, such as a blowout preventer and a production tree, to the wellhead at different times.
By way of example, a wellhead housing in the form of a casing head 18 is generally depicted in
A seal groove 36 is formed in the shoulder 34. As described further below, in some instances the seal groove 36 receives a seal to inhibit leakage from inside the wellhead housing along a path between the shoulder 34 and a component received within the pocket 30. In other instances, one or more elastomeric seals are positioned between the circumferential surface 32 and a different component received in the pocket 30 so as to inhibit leakage along a path between the surface 32 and the different component.
The upper end of the casing head 18 includes a threaded surface 40, which enables components to be connected to the upper end of the casing head 18 via threaded engagement. For instance, a drilling adapter 44 is shown coupled to the casing head 18 via a threaded collar or sleeve 46 in
Various other components may be provided inside the casing head 18, as noted above. Examples of such components are depicted in
The drilling adapter 44 can take any suitable form, but is presently depicted as a tubular drilling adapter having a lower neck and an upper flange. The lower neck is received in the pocket 30, while the upper flange can be connected to another component. For example, in at least one embodiment the drilling adapter 44 is a blowout preventer adapter in which the upper flange of the adapter 44 is fastened to a blowout preventer that is to be mounted above a wellhead. That is, the upper flange of the adapter 44 is fastened to the blowout preventer (e.g., a ram-type blowout preventer), the lower end of the adapter 44 is received within the pocket 30, and the adapter 44 is secured to the casing head 18 via threaded engagement of the collar 46 with the surface 40.
The connection of the drilling adapter 44 to the casing head 18 via the collar 46 is shown in greater detail in
One or more elastomeric or metal seals can be used to seal the connection between the upper end of the casing head 18 (or another wellhead housing having a pocket 30) and other components coupled to the casing head. During a drilling phase, an operator may prefer a drilling adapter 44 that allows a quick connection of other components (e.g., a blowout preventer) to the wellhead housing. Such an arrangement is generally depicted in
In other cases, such as during a production phase following drilling operations, metallic sealing may be desired between the casing head 18 (or other wellhead housing) and a component coupled to the casing head. For example, metal-to-metal sealing may be used when mounting a tubing head or a production tree over the casing head 18. In accordance with at least certain embodiments, the upper end of a wellhead housing body (e.g., the casing head 18) including the pocket 30 is a hybrid connector that enables alternation between quick connections of certain components to the upper end of the wellhead housing and flanged connections of other components to the upper end of the wellhead housing.
In at least one embodiment, a wellhead is converted for production following drilling operations by uncoupling the drilling adapter 44 and its attached blowout preventer from the casing head 18 and coupling some other component, such as a production tree 24, to the casing head 18 in its place. The drilling adapter 44 can be removed from the casing head 18 by unthreading the collar 46 from the threaded end 40 of the wellhead housing and then lifting the drilling adapter 44 out of the pocket 30. Once the drilling adapter 44 is removed, a threaded flange 70 can be threaded onto the surface 40 of the casing head 18, as is shown in
As further shown in
As best shown in
The flange 70 includes a threaded surface 90 that mates with the corresponding surface 40 of the casing head 18, and the additional component 78 is coupled to the casing head 18 via the flange 70. More specifically, in the presently depicted embodiment the additional component 78 is fastened to the flange 70 with a threaded connection provided by studs and nuts 92. This threaded connection can be tightened (by rotating the nuts 92 on the studs) to draw the additional component 78 toward the casing head 18 and energize the seals 86 and 88. The additional component 78 in
While the aspects of the present 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. But it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.
