Patent Application
20170159399
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 and sealing packoffs that can be installed within a bore of a wellhead. In one embodiment, a locking assembly includes an actuator that can be driven between a lock ring and another component within the bore to cause the lock ring to expand into a recess in a wall of the bore. In another embodiment, a sealing packoff includes inner and outer annular seals and an energizing ring arranged such that the energizing ring can be wedged between the inner and outer annular seals to apply a radially inward biasing on the inner annular seal and a radially outward biasing force on the outer annular seal. In at least some embodiments, the sealing packoff and the locking assembly can be axially set within the bore without requiring rotation.
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
An example of a wellhead 30 is generally depicted in
The casing head 32 is illustrated as a multi-bowl casing head that receives hangers for multiple tubular strings, including a production tubing string and intermediate casing strings. This allows a single casing head to support multiple casing strings, rather than using separate heads (e.g., a tubing head 18 and other casing heads 20) for each string. But separate tubing and casing heads could be used for supporting individual strings in other embodiments. Various locking assemblies 38 and packoffs 40 are disposed within the bore 42 of the wellhead 30 to secure the hangers and inhibit fluid leakage. In at least some embodiments, the locking assemblies 38 and the packoffs 40 are constructed for use in high and low temperatures and for high pressure within the wellhead 30 exceeding 20 ksi.
By way of example, a friction locking assembly 38 and a packoff 40 are illustrated in
The depicted locking assembly 38, which is shown in greater detail in
The locking assembly 38 is shown in its unlocked state in
Once the locking assembly 38 and the hanger 48 are axially positioned at their intended locations within the bore 42 (i.e., with the hanger 48 on landing shoulder 50 and the lock ring 54 adjacent the recesses 64), the actuator 56 can be pushed toward the landing shoulder 50 so that the actuator 56 is radially positioned between the lock ring 54 and the neck 60 of the hanger 48. This locked state is 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.
The locking assembly 38 of at least some embodiments can be set using only axial motion to secure the hanger 48 (or some other component) inside the bore 42. 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 38, 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 38, which can reduce installation time and expense. The locking assembly 38 can also be unlocked via axial force, such as by engaging recess 74 on the actuator 56 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 38 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 30 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 38 in the locked position without the need for rotation or other retention mechanisms.
For example, the actuator 56 of the locking assembly 38 depicted in
Returning now to
The packoff 40 includes an inner annular seal 80 and an outer annular seal 82. These annular seals can be formed of metal (enabling metal-to-metal sealing against other metal components) or of any other suitable material. As illustrated, the inner and outer annular seals 80 and 82 have cross-sectional profiles that include arms that extend outwardly from a central portion to seal against other components. But the annular seals 80 and 82 can be provided with different shapes in other embodiments.
The packoff 40 also includes an energizing ring 84. As discussed in greater detail below, the energizing ring 84 is shaped to be wedged between the inner annular seal 80 and the outer annular seal 82 to deflect and energize these seals by applying radially inward and outward biasing forces, respectively, to the seals. In
In one embodiment, the packoff 40 could include only one pair of annular seals (e.g., inner and outer annular seals 80 and 82). But multiple pairs of annular seals (each pair having a respective energizing ring) can be used in series in the packoff 40 to provide multiple pressure barriers. For instance, the packoff 40 in
While the packoff 40 is depicted here as having only two sets of inner and outer annular seals with associated energizing rings, further sets of seals and energizing rings could be connected in series with those described above. Each pair of inner and outer annular seals (e.g., seals 80 and 82; seals 94 and 96) can be provided as concentric ring seals that are axially aligned with one another (i.e., both intersecting a shared axial plane through the wellhead 30), as generally depicted in the present figures. But in other embodiments the seals could be provided in different arrangements, such as being axially offset from one another. The packoff 40 of
Installation and setting of the packoff 40 may be better understood with reference to
In this relaxed state, the energizing ring 84 is spaced axially apart from the landing ring 88, the energizing ring 98 is spaced axially apart from the ring 84, and the actuator 106 is spaced axially apart from the ring 98. The packoff 40 can be held together with retaining wires 110 and shear pins 112 while in its relaxed state to facilitate handling and to enable the packoff 40 to be run into the bore 42 as a single unit (e.g., in a single operation by a running tool coupled to the actuator 106). One or more shear rings can be used with or instead of the shear pins 112 in other embodiments. The packoff 40 can first be axially run into the bore 42 to the position depicted in
In one embodiment, the shear pins 112 are designed to shear in a staggered fashion. For instance, to avoid energizing the annular seals 94 and 96 before they are positioned at their desired axial location in the bore 42, the shear pin 112 through the retaining ring 90 can be configured to break first to allow energizing ring 84 to energize the seals 80 and 82. As the energizing ring 84 is driven axially downward between the seals 80 and 82, the seals 94 and 96 move into their desired axial position. The shear pin 112 through the retaining ring 100 can be configured to break next, allowing the energizing ring 98 to be driven axially downward to then energize the seals 94 and 96. The shear pin 112 holding the energizing ring 98 to the actuator 106 can then be broken to drive the lock ring 108 toward a recess in the inner component 52. Other techniques for timing the energizing of the seals and the movement of the various components of the packoff 40 (e.g., using shear rings) may also be used in full accordance with the present techniques.
The packoff 40 can be removed from the bore 42 by pulling the actuator 106 to release the lock ring 108. As the actuator 106 moves up the bore 42, the retaining wires 110 cause the energizing rings 84 and 98 to be pulled from the seals, allowing the seals to relax and the packoff 40 to be removed from the bore 42. And as noted above with respect to the locking assembly 38, the ability to axially set and remove the packoff 40 without requiring rotation can reduce the risk of damage to components of the wellhead and allow simpler tooling to be used.
In addition to simplifying installation by being axially set within a bore, the disclosed locking assemblies 38 and packoffs 40 can also enable the use of a shorter wellhead assembly. For example, by omitting separate retention devices above the locking assemblies 38, packoffs 40 can be installed closer to (e.g., in contact with) the locking assemblies 38. The seals of the packoffs 40 can also be axially set with a lower setting load and have lower preload requirements compared to wedge seals used in some other arrangements. This allows the packoffs 40 to omit both the longer, rotatable actuators (and threads) and the crushable spacers between seals of a previous arrangement, providing further space savings. In one comparison, the axial length of a combination of one locking assembly 38 and one packoff 40 (as depicted 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.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14055702 | Oct 2013 | US |
| Child | 15207326 | US |
