Patent Application
20180334876
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. 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 disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
An annular blowout preventer (BOP) is installed on a wellhead to seal and control an oil and gas well during drilling operations. A drill string may be suspended inside an oil and gas well from a rig through the annular BOP into the well bore. During drilling operations, a drilling fluid is delivered through the drill string and returned up through an annulus between the drill string and a casing that lines the well bore. In the event of a rapid invasion of formation fluid in the annulus, commonly known as a “kick,” the annular BOP may be actuated to seal the annulus and to control fluid pressure in the wellbore, thereby protecting well equipment disposed above the annular BOP. The construction of various components of the annular BOP can affect operation of the annular BOP.
Various features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein:
One or more specific embodiments of the present disclosure will be described below. These described embodiments are only exemplary of the present disclosure. Additionally, in an effort to provide a concise description of these exemplary 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.
The present embodiments are generally directed to annular blowout preventers (BOPs). Annular BOPs may include a packer assembly (e.g., an annular packer assembly) disposed within a housing (e.g., an annular housing). A piston (e.g., annular piston) may be adjusted in a first direction to drive the packer assembly from an open position to a closed position to seal an annulus around a tubular member disposed through a central bore of the annular BOP or to close the central bore. In certain disclosed embodiments, the packer assembly includes a packer (e.g., annular packer) and inserts (e.g., rigid inserts) coupled to the packer. The inserts may be arranged in a configuration that facilitates an “iris-style closing” similar to that of an iris shutter of a camera. In certain embodiments, the packer assembly may include a collapsible ring insert (e.g., annular insert) positioned proximate to a bottom axially-facing surface of the packer. As discussed in more detail below, the disclosed embodiments may facilitate stripping operations (e.g., operations in which a drill string moves through the central bore while the annular BOP is in the closed position or a partially closed position) and/or may reduce extrusion of the packer as the annular BOP moves from the open position to the closed position, thereby reducing wear on components of the annular BOP, for example.
With the foregoing in mind,
To facilitate discussion, the BOP assembly 16 and its components may be described with reference to an axial axis or direction 30, a radial axis or direction 32, and a circumferential axis or direction 34. The BOP assembly 16 may include one or more annular BOPs 42 and/or one or more ram BOPs (e.g., shear ram, blind ram, blind shear ram, pipe ram, etc.). A central bore 44 (e.g., flow bore) extends through the one or more annular BOPs 42. As discussed in more detail below, each of the annular BOPs 42 includes a packer assembly (e.g., annular packer assembly) that is configured to be mechanically squeezed radially inwardly to seal about the tubular string 24 extending through the central bore 44 (e.g., to block an annulus about the tubular string 24) and/or to block flow through the central bore 44. The disclosed embodiments include annular BOPs 42 with a packer assembly having various features, such as inserts coupled to a packer in a configuration that facilitates “iris-style closing” and/or a collapsible ring insert that supports the packer.
As discussed in more detail below, the piston 60 is configured to move relative to the housing 54 in the axial direction 30. For example, a fluid (e.g., a liquid and/or gas) may be provided to the gap 69 via a first fluid conduit 68 to drive the piston 60 upwardly in the axial direction 30, as shown by arrow 70. As the piston 60 moves upwardly, the piston 60 drives the packer 62 upwardly. For example, an axially-facing surface 72 (e.g., e.g., packer-contacting surface, top surface, upper surface, or annular surface) of the piston 60 may apply an upwardly force against an axially-facing surface 74 (e.g., piston-contacting surface, bottom surface, lower surface, or annular surface) of the packer 62, driving the packer upwardly. When driven upwardly by the piston 60, the packer 62 may move upwardly and inwardly within the top 58 to a closed position in which the packer 62 seals around the tubular string 24 extending through the central bore 44 and/or blocks fluid through the central bore 44. In some embodiments, a second fluid conduit 75 is configured to provide a fluid (e.g., a liquid and/or gas) to the gap 67 to drive the piston 60 downwardly, thereby causing the packer 62 to move into the open position 50.
In the illustrated embodiment, the packer assembly 52 includes the packer 62 and the multiple inserts 64. The multiple inserts 64 may support the packer 62 and may facilitate an “iris-style closing” to enable the packer assembly 62 to move upwardly and inwardly within the top 58 to adjust the annular BOP 42 from the open position 50 the closed position. As shown, the multiple inserts 64 are coupled to the packer 62, are positioned circumferentially about the packer 62 (e.g., at discrete locations circumferentially about the packer 62), contact a radially-inner surface 78 (e.g., curved annular surface) of the top 58, and are in an expanded position 77 while the annular BOP 42 is in the open position 50. In the expanded position 77, respective end portions 80 (e.g., radially-inner and/or upper end portions or tips) of adjacent inserts 64 are separated by a first distance 79 (e.g., along the circumferential axis 34), and opposed respective end portions 80 of opposed inserts 64 (e.g., diametrically opposed on opposite sides of the central bore 44) define a first diameter 81 (e.g., along the radial axis 32). In certain embodiments, the distance between respective end portions 80 of adjacent inserts 64 and the distance between respective end portions 80 of opposed inserts 64 may decrease as the annular BOP 42 moves from the open position 50 to the closed position.
In the illustrated embodiment, the multiple inserts 64 do not directly contact the piston 60 while the annular BOP 42 is in the open position 50. For example, the packer 62 is positioned between the multiple inserts 64 and the piston 60 along the axial axis 30, and the multiple inserts 64 are separated from the axially-facing surface 74 of the packer 62 and/or the axially-facing surface 72 of the piston 60 by an axial distance 82. While the annular BOP 42 is in the open position 50, the axial distance 82 may be equal to or greater than approximately 10, 20, 30, 40, or 50 percent of a total height 83 (e.g., along the axial axis) of the packer assembly 52. In certain embodiments, the multiple inserts 64 do not directly contact the piston 60 while the annular BOP 42 is in the open position 50, the closed position, or any position therebetween. However, in some embodiments, the multiple inserts 156 and the piston 60 may contact one another while the annular BOP 42 is in the open position 50, the closed position, and/or a position therebetween.
In operation, to move the annular BOP 42 from the open position 50 to the closed position 90, the piston 60 drives the packer assembly 52 upwardly, and the packer 62 is compressed between the top 58 and the piston 60 and the multiple inserts 64 rotate radially-inwardly (e.g., move along a spiral or parabolic path toward the center of the bore 44) in a manner similar to that of an iris shutter of a camera. As the piston 60 drives the packer assembly 52 upwardly within the housing 54, a radially-outer surface 105 (e.g., curved annular surface) of each insert 64 may slide along the radially-inner surface 78 of the top 58, and each insert 64 may be directed radially-inwardly due to the curvature of the radially-inner surface 78 of the top 58. As the packer assembly 52 moves upwardly within the top 58, a first surface 98 (e.g., side surface) of one insert 64 may move toward a second surface 100 (e.g., side surface) of an adjacent insert 64, as shown by arrow 102 (e.g., the first distance 79 between respective end portions 80 of adjacent inserts 64 decreases), and/or the first surface 98 may slide along the second surface 100, as shown by arrow 103, to enable the annular BOP 42 to move from the open position 50 to the closed position 90. In the illustrated embodiment, the multiple inserts 64 do not directly contact the piston 60 while the annular BOP 42 is in the closed position 90. For example, the packer 62 is positioned between the multiple inserts 64 and the piston 60 along the axial axis 30.
The configuration of the multiple inserts 64 may reduce extrusion of the flexible material of the packer 62 as the packer assembly 52 moves from the open position 50 to the closed position 90, for example. The configuration of the multiple inserts 64 may also facilitate stripping operations in which the tubular member 24 moves axially through the central bore 44 of the annular BOP 42, while the annular BOP 42 is in the closed position 90 or a partially closed position. For example, the tubular member 24 may include joints 104 (e.g., radially-expanded portions or connections between pipe sections that form the tubular member 24). As the joints 104 move through the central bore 44 of the annular BOP 42 during the stripping operation, the joints 104 may contact and exert a force on the respective end portions 80 of the multiple inserts 64. However, because the multiple inserts 64 are separated from the piston 60 by the packer 62 (i.e., a flexible or elastomeric component), the packer 62 may dampen the force, such that a relatively low percentage of the force is transferred to the piston 60 (e.g., as compared to some typical annular BOPs 42). Additionally or alternatively, the multiple inserts 64 may rotate radially-outwardly and/or slide relative to one another to accommodate the joint 104, thereby reducing the force transferred to the piston 60 and/or reducing wear on various components of the annular BOP 42 and/or the tubular member 24, for example.
Each insert 64 is oriented at an angle relative to the axial axis 30 and relative to the central bore 44 of the packer assembly 52, while the packer assembly 52 is in the open position 50. For example, as shown in
In the open position 50, respective end portions 80 of adjacent inserts 64 are separated by the first distance 79, and opposed respective end portions 80 of opposed inserts 64 are separated by the first diameter 81. As noted above, the distance and the diameter decrease as the packer assembly 52 moves from the open position 50 to the closed position 90. As noted above, the multiple inserts 64 move in an “iris-style closing” manner in which each insert 64 rotates radially-inwardly along a generally a spiral or parabolic path as the packer assembly 52 moves from the open position 50 to the closed position 90. For example, the first surface 98 of one insert 64 may move toward and/or slide along the second surface 100 of the adjacent insert 64, as shown by arrows 102 and 103, as the packer assembly 52 moves from the open position 50 to the closed position 90.
As shown, the multiple inserts 156 are positioned circumferentially about a first axial end 155 (e.g., upper or top end portion) of the packer 62, and the collapsible ring insert 152 extends circumferentially about a second axial end 157 (e.g., lower or bottom end portion) of the packer 62. In the illustrated embodiment, the packer 62 is positioned between the multiple inserts 156 and the collapsible ring insert 152 along the axial axis 30, and the multiple inserts 156 are separated from the collapsible ring insert 152 by an axial distance 159. Thus, the multiple inserts 156 and the collapsible ring insert 152 do not contact one another while the annular BOP 42 is in the open position 50, and may not contact one another while the annular BOP 42 is in the closed position or any position therebetween. However, in some embodiments, the multiple inserts 156 and the collapsible ring insert 152 may contact one another while the annular BOP 42 is in the open position 50, the closed position, and/or a position therebetween.
It should be appreciated that the piston 60 may contact an axially-facing surface 158 of the packer 154 and/or an axially-facing surface 160 of the collapsible ring insert 152 as the piston 60 drives the packer assembly 150 within the housing 54 of the annular BOP of
With the foregoing in mind,
Each segment 162 of the collapsible ring insert 152 may include a key portion 168 (e.g., first portion or radially-inner portion) and a slot portion 170 (e.g., second portion, radially-outer portion, or seat portion). Each key portion 168 may be received by a respective slot portion 170 of an adjacent segment 162, as shown by arrows 172, thereby moving respective key portions 168 of adjacent segments 162 toward one another, moving respective slot portions 170 of adjacent segments 162 toward one another, and enabling transition from the expanded position 164 to the collapsed position.
As shown, the respective slot portions 170 of adjacent segments 162 are separated from one another by a gap 174 (e.g., circumferential gap) while the collapsible ring insert 152 is in the expanded position 164, and a circumferential distance 176 across the gap 174 may decrease as the collapsible ring insert 152 moves from the expanded position 164 to the collapsed position. Similarly, the respective key portions 168 of adjacent segments 162 are separated from one another by a gap 178 (e.g., circumferential gap) while the collapsible ring insert 152 is in the expanded position 164, and a circumferential distance 180 across the gap 178 decreases as the collapsible ring insert 152 moves from the expanded position 164 to the collapsed position.
As shown in
Any of the features disclosed above may be combined or used together in any of a variety of manners. For example, the collapsible ring insert 152 illustrated in
While the 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. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims.
