Patent Application
20220325595
Embodiments of the subject matter disclosed herein generally relate to subsea oil and gas pressure containment equipment. More particularly, the present technology relates to annular blowout preventors.
A blowout preventer assembly is employed for offshore well drilling operations. The blowout preventer assembly includes a blowout preventer stack (BOP stack) that includes several ram preventers. The BOP stack lands on and connects to a wellhead housing either on the surface or on the sea floor. A surface BOP stack is configured with an annular BOP connected to several ram BOPs below with a connector on bottom that connects to a wellhead or high pressure housing. A subsea stack is configured with a lower marine riser package (LMRP) configured with one or two annular BOPs that connect to a tubular mandrel on the upper end of the lower BOP stack, which is configured with multiple ram BOPs with a connector on bottom for connecting to a subsea wellhead. The LMRP secures to a lower end of the riser and has control pods that control various functions of the BOP stack and LMRP. The LMRP also has one or more annular blowout preventers, which can seal around pipe of a variety of sizes as well as completely close the passage.
Both surface stacks and subsea stacks are large pieces of equipment, and are quite tall. It would be desirable to reduce the overall height and weight of the BOP assembly because of height restrictions when the equipment is stowed on the rig. A reduced height would allow the use of the equipment on rigs with a lower deck height and reduce the center of gravity and overall bending moment on a subsea wellhead. A reduced height and weight would allow for smaller rig designs or allow existing rigs to increase their operational limits. It would also allow for the installation of an additional ram BOP preventer in the BOP stack without adding the full height of the additional ram to the assembled BOP stack and LMRP. More generally, a reduced height annular BOP may be desirable for these and other reasons.
One embodiment of the present technology provides an annular blowout preventer (BOP). The annular BOP includes an annular housing having a base. The base includes a plurality of fasteners extending from an interior of the housing to an exterior of the housing via fastener holes formed through the connector base. The annular BOP further includes a seal plate positioned at least partially adjacent interior ends of the plurality of fastener. The annular BOP further includes an annular elastomeric element positioned within the interior of the housing and an annular piston positioned within the interior of the housing. The piston, when driven towards the elastomeric element, deforms the elastomeric element and forces the elastomeric element to constrict radially inward.
Another embodiment of the present technology provides subsea system which includes a riser coupled to a vessel, a lower marine riser package coupled to the riser opposite the vessel, and an annular blowout preventer (BOP) coupled to the lower marine riser package. The BOP includes an annular housing having a base. The base includes a plurality of fasteners extending from an interior of the housing to an exterior of the housing via fastener holes formed through the base. The annular BOP also includes a seal plate positioned at least partially adjacent interior ends of the plurality of fasteners, an annular elastomeric element positioned within the interior of the housing, and an annular piston positioned within the interior of the housing. The piston, when driven towards the elastomeric element, deforms the elastomeric element and forces the elastomeric element to constrict radially inward. The subsea system further includes one or more ram BOPs coupled to the annular BOP.
Another embodiment of the present technology provides a method of installing an annular blowout preventer (BOP). The method includes placing a body of a housing of the annular BOP onto a ram BOP or subsea equipment, wherein the body has a base with a plurality of fastener holes formed therethrough. The method further includes securing the body to a ram BOP or the subsea equipment with a plurality of fasteners inserted through the plurality of fastener holes. The plurality of fastener holes is sealed off from the wellbore and hydraulic chamber to prevent leakage to the environment. The method further includes placing a top portion of the annular BOP onto the body. The top portion includes a cap, an elastomeric element, and a piston. The cap couples with the body to form the housing and enclose the elastomeric element and piston inside of the housing.
The present technology can be better understood on reading the following detailed description of nonlimiting embodiments thereof, and on examining the accompanying drawings, in which:
The foregoing aspects, features, and advantages of the present technology can be further appreciated when considered with reference to the following description of preferred embodiments and accompanying drawings, wherein like reference numerals represent like elements. The following is directed to various exemplary embodiments of the disclosure. The embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, those having ordinary skill in the art can appreciate that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.
Referring to
In some embodiments, the annular housing 31 is comprised of a body 43 and a cap 45, in which the body 43 forms a bottom portion of the annular housing 31 and the cap 45 forms a top portion of the annular housing 31. The body 43 and the cap 45 are secured to each other to form the annular housing 31 and contain the piston 37 and the elastomeric element 41. In some embodiments, the cap 45 secures to the body 43 with a locking member 47. Cap 45 has a concentric upper opening 49 with a diameter the same or smaller than the diameter of central passage of the elastomeric element 41 when the elastomeric element 41 is not being deformed. A concentric lower opening 51 is located at a lower end of the body 43 and is the same or smaller diameter as upper opening 49.
The body 43 includes a connector base 39 located at the bottom of the annular BOP 29 and configured to connect the annular BOP 29 to another piece of equipment, such as a ram BOP or connector 27 (
Referring still to
A recessed chamber 67 is formed adjacent the fastener holes 53 to accommodate the fasteners 55 and stud nuts 65, and allows for sealing the region from the rest of annular BOP 29. Specifically, the recessed chamber 67 is sealed by the seal plate 57 and the first and second seals 59, 69. In some embodiments, a vent port 71 is formed in the housing 31 and communicatively couples the recessed chamber 67 to outside of the housing annular BOP 29. This allows for any leaks in the recessed chamber 67 to be detected, such as from wellbore fluids that may have moved past the piston sleeve seal 72 and/or hydraulic closing chamber seals 59 and 69.
The annular BOP 29 of the present disclosure provides a way to create a connect between the annular BOP 29 and a ram BOP or a connector on a subsea stack to connect to the BOP stack 11 without the need for a connection flange, which is how the connection is conventionally made. The connection flange adds additional height and weight to the annular BOP 29. Thus, the present annular BOP 29 which is connectable directly from the base of the housing does not require the flange and thus can be shorter overall.
While the present disclosure has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, can appreciate that other embodiments may be devised which do not depart from the scope of the disclosure as described herein. Accordingly, the scope of the disclosure should be limited only by the attached claims.
