Patent Application
20180313180
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 wellhead assemblies mounted on wells through which resources are accessed or extracted. Such wellhead assemblies can include a wide variety of components, such as various spools, casings, valves, pumps, fluid conduits, and the like, that control drilling or extraction operations. In many instances, casings are coupled to wellheads via hangers installed in bores of the wellheads. These hangers and other components within the bores can be retained in various ways, and sealing packoffs can be used to seal annular spaces within the bores.
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 locking assemblies that can be used to secure components in bores and to retaining rings for retaining the locking assemblies in locked positions within the bores. In one embodiment, a locking assembly is used to secure a hanger in a wellhead bore. The locking assembly includes a lock ring and an actuator that is moved to a locked position to drive the lock ring into engagement with a mating surface to secure the hanger in the bore. A retaining ring is positioned over the locking assembly to inhibit unsetting of the actuator from the locked position. In at least some instances, the retaining ring and the actuator have mating tapered surfaces that cooperate to oppose movement of the actuator out of the locked position.
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
By way of example, components of an apparatus 40 with a wellhead hanger 48 and a friction locking assembly 50 for securing the wellhead hanger 48 within a bore are illustrated in
In
As depicted in
The actuator 56 can be moved axially along the neck 60 to lock and unlock the assembly 50. More specifically, the actuator 56 can be wedged between the neck 60 and the lock ring 54 to cause the lock ring 54 to expand into engagement with the recesses 64, and the actuator 56 can be at least partially withdrawn from between the neck 60 and the lock ring 54 to allow the lock ring 54 to contract and disengage from the recesses 64. In its unlocked state, the locking assembly 50 can be moved (e.g., carried by the hanger 48) axially within the bore of the wellhead component 42, such as during installation of the hanger 48 in the bore. Once the locking assembly 50 and the hanger 48 are axially positioned at their intended locations within the bore (i.e., with the hanger 48 on the landing shoulder of the wellhead component 42 and the lock ring 54 adjacent to the recesses 64), the actuator 56 can be pushed axially downward along the neck 60 toward the landing shoulder so that the actuator 56 is radially positioned between the lock ring 54 and the neck 60 of the hanger 48.
Examples of this locked state are depicted in
A tapered interface 68 of the lock ring 54 and the actuator 56 causes the lock ring 54 to expand radially as the actuator 56 is driven between the lock ring 54 and the neck 60. To facilitate this radial expansion, the lock ring 54 is provided as a split ring (e.g., a C-ring) in at least some embodiments. The expansion of the lock ring 54 results in the movement of the ridges 62 into the recesses 64, which inhibits axial movement of the hanger 48 within the bore 42.
Once run into the bore of the wellhead component 42, the locking assembly 50 of at least some embodiments can be set using only axial motion to secure the hanger 48 (or some other component) inside the bore. Unlike other locking assemblies that require rotation of an element (such as a threaded ring) within bores to set the locking assemblies and secure components within the bores, the presently depicted locking assembly can be set by axially driving (e.g., with a running tool) the actuator 56 between the lock ring 54 and the hanger 48 to cause the lock ring 54 to engage the recesses 64. Rotation of components within a bore can increase the risk of damage to the bore and other components. By axially setting the locking assembly 50, such an increased risk of damage from rotation can be avoided. Axial setting also allows the use of less complicated tooling in installing the locking assembly 50, which can reduce installation time and expense. The locking assembly 50 can also be unlocked via axial force, such as by engaging an upper end of the actuator 56 with a tool and pulling the actuator 56 away from the load ring 58 to allow the lock ring 54 to relax and retract from the recesses 64.
Further, when in its locked position, the locking assembly 50 provides a preload on the hanger 48. This preload in some instances can be equal to the expected loading on the hanger 48 from wellbore fluids in the wellhead during operation. As depicted in
In some prior art designs, locking assemblies in wellheads are retained by providing devices, such as springs, above the locking assemblies to load against the locking assemblies and inhibit axial movement. In other prior art designs, threaded connections are used to retain locking assemblies at a desired location. But in contrast to such prior art designs, in at least some embodiments of the present disclosure friction alone is used to retain a locking assembly 50 in the locked position without the need for rotation or other retention mechanisms.
For example, the actuator 56 of the locking assembly 50 depicted in
As noted above, stack-up tolerances, deflections, or other factors can cause variation in the height of the actuator 56 (i.e., its position along the neck 60) when set in the locked position. The steep taper between the actuator 56 and the lock ring 54 at the tapered interface 68 generally compounds this variation. Because of the uncertainty of the height position of the actuator 56 in a given application, verification of the proper setting of the locking assembly 50 can be difficult. Consequently, in at least some embodiments the hanger apparatus 40 includes a retaining ring 52 that accommodates variation in the locking position of the actuator 56.
As shown in
While the actuator 56 may be primarily retained through friction along interfaces 66 and 68 (i.e., friction with the neck 60 and the lock ring 54), vibration, shock loads, or other forces could cause movement of the actuator 56 along the neck 60 away from the locked position. A secondary retention mechanism, such as the retaining ring 52, can be used to prevent inadvertent unsetting of the actuator 56 if friction with the neck 60 and the lock ring 54 is insufficient to hold the actuator 56 in the locked position. In such an instance, upward movement of the actuator 56 along the neck 60 would increase hoop deflection in the retaining ring 52, allowing the stiffness of the retaining ring 52 to create an increasing retention load on the actuator 56 that inhibits movement of the actuator 56 out of engagement with the lock ring 54. That is, given the tapered surfaces of the interface 80, the retention load applied by the retaining ring 52 continues to increase as the actuator 56 moves upward. In
Another example of the retaining ring 52 is depicted in
An additional example of the actuator 56 in its locked state at lower and upper axial positions is shown in
As will be appreciated, each of the various locking assemblies 50 described above can be run into the bore of a wellhead component 42 and, once positioned, the actuator 56 can be moved to a locked position to drive the lock ring 54 into engagement with the wellhead component 42 and secure the wellhead hanger 48 or another component within the bore. In some instances, the locking assembly 50 is run into the bore with the hanger 48. The retaining ring 52 can also be lowered into the bore with the locking assembly 50, or after the locking assembly 50 is run into the bore, and positioned so that the mating surfaces of the tapered interface 80 oppose movement of the actuator 56 along the hanger 48 toward an unlocked position.
A packoff can be installed in the bore above the locking assembly 50. In the presently depicted embodiments, the retaining ring 52 is provided as part of such a packoff (i.e., a packoff landing ring) and the retaining ring 52 is lowered into the bore as part of the packoff. By omitting a separate retention device between a packoff and the locking assembly 50, the packoff can be installed closer to (e.g., in contact with) the locking assembly 50, which enables the use of a shorter wellhead assembly. But the retaining ring 52 could be provided independent of a packoff in other embodiments.
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.
