PILOT BLOCK SYSTEM TO LOCK A BLOWOUT PREVENTER STACK

BACKGROUND

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.

A blowout preventer (BOP) stack is installed on a wellhead to seal and control an oil and gas well during drilling operations. During drilling operations, a drill string may extend through the BOP stack into a wellbore. Further, 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 wellbore. In the event of a rapid invasion of formation fluid in the annulus, commonly known as a “kick,” a movable component within the BOP stack may be actuated to seal the annulus and to control fluid pressure in the wellbore, thereby protecting well equipment disposed above the BOP stack. In some cases, a lock system may also be operated to lock the movable component to maintain the seal in the annulus.

BRIEF DESCRIPTION

A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

In certain embodiments, a lock system includes a lock assembly for a movable component, a lock line configured to apply pressure to actuate the lock assembly, and a close line configured to apply pressure to close the movable component. The lock system also includes a pilot block with a respective pilot-operated check valve along the lock line, wherein the pilot block is actuated via a respective target pressure in the close line.

In certain embodiments, a method of operating a lock system includes providing a closing flow of hydraulic fluid through a close line to adjust a movable component to a closed position. The method also includes actuating a pilot block via sufficient pressure of the closing flow of hydraulic fluid in the close line. The method further includes providing a locking flow of hydraulic fluid through a lock line and across the pilot block to adjust a lock member of a lock assembly to a lock position to maintain the movable component in the closed position.

In certain embodiments, a system includes a movable component, a movable component actuator configured to drive the movable component between an open position and a closed position, a lock member, and a lock actuator configured to drive the lock member between an unlock position and a lock position. The system further includes a pilot block with at least one pilot-operated check valve across a lock line that fluidly couples a hydraulic fluid source to the lock actuator, wherein the at least one pilot-actuated check valve is configured to be actuated via application of sufficient pressure in a close line that fluidly couples the hydraulic fluid source to the movable component actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 is a block diagram of a mineral extraction system, in accordance with an embodiment of the present disclosure;

FIG. 2 is a cross-sectional side view of a blowout preventer (BOP) that may be used in the mineral extraction system of FIG. 1, wherein rams are withdrawn from a central bore of the BOP, in accordance with an embodiment of the present disclosure;

FIG. 3 is a cross-sectional side view of the BOP of FIG. 2, wherein the rams are within the central bore of the BOP, in accordance with an embodiment of the present disclosure;

FIG. 4 is a perspective front view of an embodiment of a rotary lock that may utilized with the BOP of FIGS. 2 and 3, in accordance with an embodiment of the present disclosure;

FIG. 5 is a cut-away perspective rear view of the rotary lock of FIG. 4, in accordance with an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of a lock system for a BOP stack that may be used in the mineral extraction system of FIG. 1, wherein the lock system locks a first BOP of the BOP stack, in accordance with an embodiment of the present disclosure;

FIG. 7 is a schematic diagram of the lock system of FIG. 6, wherein the lock system unlocks the first BOP of the BOP stack, in accordance with an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of a lock system for a BOP stack that may be used in the mineral extraction system of FIG. 1, wherein the lock system locks a first BOP of the BOP stack and includes at least one common line, in accordance with an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of the lock system of FIG. 12, wherein the lock system unlocks the first BOP of the of the BOP stack, in accordance with an embodiment of the present disclosure;

FIG. 10 is a schematic diagram of a pilot block that includes a flow regulator, in accordance with an embodiment of the present disclosure;

FIG. 11 is a perspective top view of a BOP that may be used in the mineral extraction system of FIG. 1, wherein a pilot block is coupled to a body of the BOP, in accordance with an embodiment of the present disclosure;

FIG. 12 is a perspective top view of the pilot block of FIG. 11, in accordance with an embodiment of the present disclosure;

FIG. 13 is a perspective top view of the pilot block of FIGS. 11 and 12, in accordance with an embodiment of the present disclosure; and

FIG. 14 is a flow diagram of a method of operating a lock system, such as the lock system of FIGS. 6 and 7 and/or the lock system of FIGS. 8 and 9, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

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.

When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” “having,” and “based on” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Further, numerical terms, such as “first,” “second,” “third,” and so forth, are merely used herein to facilitate discussion of various separate components and may be used differently in the description and the claims.

The present embodiments are generally directed to a lock system, which may be used to lock and unlock one or more rams of a blowout preventer (BOP). For example, each ram may be configured to adjust from an initial ram position (e.g., open position; first position) in which the ram is withdrawn from a central bore of the BOP to a final ram position (e.g., closed position; second position) in which the ram is positioned within the central bore of the BOP. The lock system may include one or more lock members (e.g., locking screws), and each lock member may be configured to adjust from an unlock position (e.g., a first lock member position) in which the lock member does not block movement of the ram to a lock position (e.g., a second lock member position) in which the lock member locks the ram in the final ram position (e.g., to block the movement of the ram from the final ram position to the initial ram position; to block withdrawal/movement of the ram backward from the central bore).

As discussed in more detail herein, the lock system may include a pilot block associated with the BOP. The pilot block includes two pilot operated check valves, and the pilot block allows adjustment of the one or more lock members between the unlock position and the lock position in response to (e.g., only during) sufficient pressure in a close line coupled to the BOP. Further, the sufficient pressure in the close line corresponds to a target or threshold pressure that drives the ram to the final ram position, thus the pilot block allows adjustment of the one or more lock members between the unlock position and the lock position in response to (e.g., only during) the ram being in the final ram position (e.g., the BOP is in a closed configuration). In certain embodiments, the lock system may include a flow regulator, and the flow regulator may be coupled to (e.g., incorporated into; integrated with) the pilot block. For example, a pilot block housing may support (e.g., house; surround) the two pilot operated check valves and the flow regulator. Further, a fire shield may be coupled to (e.g., included as part of; fastened to) the pilot block housing to provide protection to components within the pilot block housing, such as to protect the two pilot operated check valves and/or the flow regulator and/or enable operation of the two pilot operated check valves and/or the flow regulator even when certain conditions (e.g., fire; extreme temperature) are present around the pilot block housing.

Advantageously, the lock system may be used to lock and unlock one or more respective rams of multiple BOPs of a BOP stack. In such cases, each BOP may be associated with a respective pilot block. The respective pilot block may operate to allow adjustment of one or more respective lock members between the unlock position and the lock position in response to (e.g., only during) sufficient pressure in a respective close line coupled to the respective BOP. In this way, each BOP in the BOP stack may be separately locked and unlocked via the lock system in response to (e.g., only during) sufficient pressure in the respective close line coupled to the respective BOP. It should be appreciated that each pilot block may be associated with a respective flow regulator. That is, each pilot block may include a respective pilot block housing that supports respective pilot operated check valves and the respective flow regulator. The lock system described herein may be particularly useful in contexts and configurations with multiple BOPs in a BOP stack, as one lock input (e.g., lock button; lock command) and one unlock input (e.g., unlock button; unlock command) may enable each BOP in the BOP stack to be locked and unlocked via the lock system as long as there is sufficient pressure in the respective close line coupled to the respective BOP.

Further, the lock system described herein may be particularly useful in contexts and configurations with one or more lock members coaxial with one or more rams (or actuators that drive the one or more rams), or that are otherwise configured to apply and remove axial force at the one or more rams (e.g., the axial force toward a bore of the BOP) to provide lock and unlock functions. For example, the pilot block may prevent the one or more lock members from applying the axial force to the one or more rams to drive the one or more rams from the initial ram position to the final ram position. Instead, the pilot block may enable (e.g., only allow) the one or more lock members to apply the axial force to the one or more rams while the one or more rams are in the final ram position (e.g., after application of sufficient pressure in the closing line to move the one or more rams to the final ram position). It should be appreciated that the lock system described herein may provide solutions for unique considerations related to use of one locking line and one unlocking line with such coaxial and/or axial force configurations. For example, certain existing lock systems that are not coaxial and/or that move lock members transverse to the one or more rams merely apply non-axial force (e.g., lateral or transverse) against actuators that drive the one or more rams, which does not damage components and does not inadvertently drive the one or more rams to the final ram position.

To facilitate discussion, certain embodiments described herein include a rotary lock as part of the lock system. However, it should be appreciated that any of a variety of lock types and configurations may be implemented as part of the lock system, such as any of a variety of lock types and configures that apply and remove axial force at the one or more rams to provide lock and unlock functions. Further, while the disclosed embodiments are described in the context of a BOP or a BOP stack of a drilling system to facilitate discussion, it should be appreciated that the lock system may be adapted for use in other contexts and other operations. As one example, the BOP or the BOP stack may be used in a pressure control equipment (PCE) stack that is coupled to and/or positioned vertically above a wellhead during various intervention operations (e.g., inspection or service operations), such as wireline operations in which a tool supported on a wireline is lowered through the PCE stack to enable inspection and/or maintenance of a well. In such cases, the BOP(s) may be adjusted from an open configuration (e.g., open position) to a closed configuration (e.g., closed position (e.g., to seal around the wireline extending through the PCE stack) to isolate the environment, as well as other surface equipment, from pressurized fluid within the well. As another example, the lock system may be employed to lock other components in any of a variety mechanical systems, hydraulic systems, and so forth.

With the foregoing in mind, FIG. 1 is a block diagram of an embodiment of a mineral extraction system 10. The mineral extraction system 10 may be configured to extract various minerals and natural resources, including hydrocarbons (e.g., oil and/or natural gas), from the earth, or to inject substances into the earth. The mineral extraction system 10 may be a land-based system (e.g., a surface system) or an offshore system (e.g., an offshore platform system). A BOP stack 16 is mounted to a wellhead 18, which is coupled to a mineral deposit via a wellbore 26. The wellhead 18 may include any of a variety of other components, such as a spool, a hanger, and a “Christmas” tree. The wellhead 18 may return drilling fluid or mud to the surface 12 during drilling operations, for example. Downhole operations are carried out by a conduit 24 that extends through the BOP stack 16, through the wellhead 18, and into the wellbore 26.

To facilitate discussion, the BOP stack 16 and its components may be described with reference to a vertical axis or direction 30, a longitudinal axis or direction 32 (also referred to herein as an axial axis or direction), and a lateral axis or direction 34. The BOP stack 16 may include one or more BOPs 42 (e.g., 1, 2, 3, 4, 5, 6, 7, 8 or more ram BOPs) stacked relative to one another. A central bore 44 (e.g., flow bore) extends through the one or more BOPs 42. As discussed in more detail herein, a lock system (e.g., a cavity lock system) may provide one lock input (e.g., lock button; lock command) and one unlock input (e.g., unlock button; unlock command) to enable each BOP 42 in the BOP stack 16 to be separately locked and unlocked via the lock system in response to (e.g., only during) sufficient pressure in a respective close line coupled to the respective BOP 42.

FIGS. 2 and 3 are cross-sectional side views of an embodiment of a BOP 42 that may be used in the mineral extraction system 10 of FIG. 1. In FIG. 2, each ram 50 of the BOP 42 is in an initial ram position (e.g., open position; first position). In the initial ram position, each ram 50 is withdrawn from the central bore 44, enables a fluid flow through the central bore 44, does not contact the conduit 24, and/or does not contact a corresponding opposed ram 50. In FIG. 3, each ram 50 of the BOP 42 is in a final ram position (e.g., closed position; second position). In the final ram position, the ram 50 extends into the central bore 44, blocks the fluid flow through the central bore 44, contacts the conduit 24, and/or contacts the corresponding opposed ram 50. While the ram 50 is in the initial ram position, the BOP 42 may be in an open configuration 56 (e.g., open position) in which the BOP 42 enables the fluid flow through the central bore 44. While each ram 50 is in the final ram position, the BOP 42 may be in a closed configuration 58 (e.g., closed position) in which the BOP 42 blocks the fluid flow through the central bore 44. For example, each ram 50 may include a ram body 60 and a sealing element 62 (e.g., packer), and the sealing elements 62 of the opposed rams 50 may contact and seal against the conduit 24 to thereby seal an annulus about the conduit 24 to block the fluid flow through the central bore 44. It should be appreciated that the rams 50 may be configured to seal the central bore 44 without the conduit 24 (e.g., the sealing elements 62 of the opposed rams 50 may contact and seal against one another to seal the central bore 44).

As shown, the BOP 42 includes a body 70 that houses each ram 50. In particular, the central bore 44 has a bore central axis 72 (e.g., aligned with the vertical axis 30) and extends through the body 70. The body 70 also defines a cavity 74 (e.g., ram cavity) that has a cavity central axis 76 (e.g., aligned with the longitudinal axis 32) and intersects the central bore 44 (e.g., the bore central axis 72 and the cavity central axis 76 are transverse or orthogonal to one another). This configuration enables each ram 50 to move between the initial position in which the ram 50 is withdrawn from the central bore 44 and positioned within the cavity 74 to the final position in which the ram 50 is positioned within the central bore 44 and extends from cavity 74.

The body 70 may also house components of an actuator assembly 80 that drives each ram 50 between the initial ram position and the final ram position. For example, in the illustrated embodiment, the actuator assembly 80 includes a respective piston 82 and a respective connecting rod 84 for each ram 50. In operation, upon an increase in wellbore pressure or upon another indication that the BOP 42 should be adjusted to the closed configuration 58, a hydraulic fluid may be provided through a close line into a respective piston cavity 86 to drive the respective pistons 82, as well as the respective connecting rods 84 and the respective rams 50 coupled thereto, toward the central bore 44. In this way, each ram 50 may be driven from the initial ram position of FIG. 2 to the final ram position of FIG. 3. As shown, various seals 118 (e.g., annular seals) may be provided to seal and/or to isolate certain cavities.

While the body 70 is illustrated as a one-piece body that encompasses both the rams 50 and the pistons 82 to facilitate discussion, it should be appreciated that the body 70 may include a first body that encompasses the rams 50 and a second body that encompasses the pistons 82. In such cases, the first body may be a BOP ram body and the second housing may be a bonnet body, and the BOP ram body and the bonnet body may be coupled to one another (e.g., via fasteners).

As shown, the BOP 42 may include or be associated with a lock system 88 (e.g., cavity lock system) that includes one or more lock assemblies 90 with one or more lock members 92. In the illustrated embodiment, one lock member 92 is provided for each ram 50 (e.g., a first lock member and a second lock member positioned on opposite sides of the rams 50 along the longitudinal axis 32). Additionally, it should be appreciated that the one or more lock members 92 may have any of a variety of configurations (e.g., cross-sectional shapes, sizes, positions) and may move in any of a variety of ways.

Each lock member 92 is configured to move from a first lock position (e.g., unlocked position or configuration), which is shown in FIG. 2, to a second lock position (e.g., locked position or configuration), which is shown in FIG. 3. In the first lock position, the lock member 92 may be withdrawn relative to the body 70 and does not block movement of the ram 50. In the second lock position, the lock member 92 may be extended relative to the body 70 and blocks movement of the ram 50 (e.g., via contact with the actuator assembly 80). In particular, the lock member 92 is configured to engage (e.g., contact) the piston 82 (e.g., a tailrod portion of the piston 82) to block movement of the ram 50 from the final ram position to the initial ram position (e.g., the block withdrawal of the ram 50 from the central bore 44), thereby locking the ram 50 in the final ram position to lock the BOP 42 in the closed configuration 58.

Further, each lock member 92 is configured to move from the second lock position, which is shown in FIG. 3, to the first lock position, which is shown in FIG. 2. In particular, the lock member 92 is configured to be withdrawn relative to the body 70 to disengage from (e.g., separate from or remove contact with) and/or to remove axial force applied to the piston 82 (e.g., the tailrod portion of the piston 82) to enable the ram 50 to move from the final ram position to the initial ram position (e.g., to enable the ram 50 to be withdrawn from the central bore 44), thereby unlocking the ram 50 from the final ram position. As discussed in more detail herein, the lock system 88 includes a pilot block with two pilot operated check valves for the BOP 42, which enables the lock member 92 to perform locking and unlocking functions for the BOP 42 while the ram 50 is in the final ram position and the BOP 42 is in the closed configured 58.

With reference to FIG. 3, an actuator-contacting surface 108 (e.g., longitudinally-facing surface) of the lock member 92 may contact a lock-contacting surface 110 (e.g., longitudinally-facing surface) of the piston 82. In the illustrated embodiment, the lock-contacting surface 110 of the piston 82 faces away from the central bore 44 and/or is a rearmost surface of the piston 82 (e.g., furthest from the central bore 44). However, it should be appreciated that the lock member 92 may be configured to contact and engage another surface of the piston 82 or any other surface of the actuator assembly 80 and/or the ram 50 (e.g., a surface; a recess formed in a surface). Furthermore, while the illustrated embodiment shows the lock member 92 extending and moving longitudinally relative to the body 70 (e.g., along the longitudinal axis 32), and while the lock system 88 may be particularly useful in such configurations, it should be appreciated that the lock member 92 may extend and move laterally (e.g., along the lateral axis 34) and/or vertically (e.g., along the vertical axis 30). For example, instead of or in addition to being positioned on opposite sides of the body 70 along the longitudinal axis 32, the lock members 92 may be positioned on opposite sides of the body 70 along the lateral axis 34.

The movement of the ram 50 and the movement of the lock member 92 may be carried out based on inputs to a controller 112 (e.g., an electronic controller; a control panel). For example, the controller 112 may control (e.g., via actuation of a valve) a flow of the hydraulic fluid through the closing line to the respective piston cavity 86 to drive the ram 50 into the central bore 44 in response to a close input (e.g., actuation of a button or a switch; command) at the controller 112. Similarly, the controller 112 may control (e.g., via actuation of a valve) the flow of the hydraulic fluid through an open line to the respective piston cavity 86 to withdraw the ram 50 from the central bore 44 in response to an open input (e.g., actuation of a button or a switch; command) at the controller 112. The controller 112 may also control (e.g., via actuation of respective valves) a flow of a hydraulic fluid to the pilot block to initiate lock and unlock functions with the lock system 88. However, as described in more detail herein, the pilot block may block or prevent the flow of hydraulic fluid unless there is sufficient pressure in the closing line.

FIG. 4 is a perspective front view of an embodiment of one lock assembly 90, and FIG. 5 is a cut-away perspective rear view of one lock assembly 90. As shown, the lock assembly 90 is a rotary lock assembly and includes a lock housing 120 that surrounds the lock member 92. The lock housing 120 may be configured to couple to the body 70 of the BOP 42. As noted above, the body 70 of the BOP 42 may be a unitary body or a multi-part body. Regardless of the configuration of the body 70, the piston 82 of the actuator assembly 80 may be supported within some portion of the body 70.

The lock assembly 90 also includes a gear box housing 130 that supports a gear box 132. The lock assembly 90 also includes an engine housing 142 that supports a rotary engine and associated components (e.g., additional gears to transfer torque from the rotary engine). An output shaft driven by the rotary engine may extend into the gear box 132 to drive gear components of the gear box 132. While the lock housing 120, the gear box housing 130, and the engine housing 142 are shown as separate housings that are fastened to one another (e.g., via fasteners), it should be appreciated that these housings may have any suitable form or configuration.

With reference to FIG. 5, the lock housing 120 surrounds the lock member 92 and a stem 152 that engages the lock member 92. An end portion 154 of the stem 152 extends from (e.g., one-piece construction) and/or is coupled (e.g., non-rotatably) to the gear components of the gear box, such as via a fastener 158. In operation, rotation of the gear components of the gear box drives rotation of the stem 152, which drives rotation of the lock member 92. The stem 152 engages the lock member 92 in a manner that enables the stem 152 to drive the rotation of the lock member 92, while also enabling the lock member 92 to move longitudinally relative to the stem 152 (e.g., toward and away from the fastener 158). For example, a radially-outer surface of the stem 152 may include one or more radially-extending tabs that engage one or more longitudinally-extending recesses on a radially-inner surface of the lock member 92. Furthermore, a radially-outer surface of the lock member 92 may include threads that engage corresponding threads on a radially-inner surface of a chamber 162 defined within the lock housing 120. Thus, the lock member 92 may be an annular, threaded structure, such as an annular threaded lock screw. The lock member 92 and the stem 152 may be coaxial, such as along a center lock axis 156. The center lock axis 156 may be aligned with the longitudinal axis 32 and/or may be coaxial with the cavity central axis 76 shown in FIGS. 2 and 3.

In operation, the rotation of the lock member 92 may move the lock member 92 longitudinally through the chamber 162 of the lock housing 120. For example, rotation of the lock member 92 in a first rotational direction may move the lock member 92 in a first longitudinal direction, as shown by arrow 164. Additionally, rotation of the lock member 92 in a second rotational direction may move the lock member 92 in a second longitudinal direction, as shown by arrow 166. In this way, the rotation of the lock member 92 (e.g., via the rotary engine and the gear box 132) adjusts the lock member 92 between the first lock position and the second lock position, as described herein with respect to FIGS. 1-3. Also, while the lock assembly 90 and its components may be described with reference to the vertical axis or direction 30, the longitudinal axis or direction 32, and the lateral axis or direction 34 that are also referenced in FIGS. 1-3, it should be appreciated that the lock assembly 90 may be oriented and positioned in different manners relative to the BOP 42.

FIG. 6 is a schematic diagram of an embodiment of the lock system 88, wherein the lock system 88 locks at least one BOP 42 of a BOP stack 16. As shown, the BOP stack 16 includes a first BOP 42A, a second BOP 42B, and a third BOP 42C. However, it should be appreciated that the BOP stack 16 may include any number of BOPs 42. Each BOP 42 is associated with a respective close line 202, such as a first close line 202A for the first BOP 42A, a second close line 202B for the second BOP 42B, and a third close line 202C the third BOP 42C. Additionally, each BOP 42 is associated with a respective open line 204, such as a first open line 204A for the first BOP 42A, a second open line 204B for the second BOP 42B, and a third open line 204C the third BOP 42C.

As shown, the controller 112 may include input devices 206, 208, such as a first close input device 206A and a first open input device 208A for the first BOP 42A, a second close input device 206B and a second open input device 208B for the second BOP 42B, a third close input device 206C and a third open input device 208C for the third BOP 42C. In operation, an operator may provide a close input to the first close input device 206A, which may cause a flow of hydraulic fluid to a respective portion of the first BOP 42A to transition or drive the first BOP 42A to the closed configuration 58. Similarly, the operator may provide an open to input the first open input device 208A, which may cause a flow of hydraulic fluid to a respective portion of the first BOP 42A to transition or drive the first BOP 42A to the open configuration 56. It should be appreciated that the operator may provide separate inputs to selectively open and close any of the BOPs 42, such as based on desired operational effects (e.g., shearing, sealing, blind sealing). Thus, as shown in FIG. 6, the first BOP 42A is in the closed configuration 58, while the second BOP 42B and the third BOP 42C are in the open configuration 56.

Further, each BOP 42 is associated with a respective pilot block 210, such as a first pilot block 210A for the first BOP 42A, a second pilot block 210B for the second BOP 42B, and a third pilot block 210C for the third BOP 42C. Each pilot block 210 is actuated via pressure applied via a respective close line 202. For example, the first pilot block 210A is fluidly coupled to the first close line 202A and actuated by sufficient pressure (e.g., a target or threshold pressure) within the first close line 202A, the second pilot block 210B is fluidly coupled to the second close line 202B and actuated by sufficient pressure (e.g., a target or threshold pressure) within the second close line 202B, and the third pilot block 210C is fluidly coupled to the third close line 202C and actuated by sufficient pressure (e.g., a target or threshold pressure) within the third close line 202C. The sufficient pressure corresponds to a target or threshold pressure to transition the respective BOP 42 to the closed configuration 58, thus the respective pilot block 210 is actuated in response to (e.g., only during) the respective BOP 42 being in the closed configuration 58.

Each pilot block 210 also includes a respective first check valve 212 that is fluidly coupled to a lock line 216 and a respective second check valve 214 that is fluidly coupled to an unlock line 218. In operation, the operator may provide a lock input to a lock input device 220, which may cause a flow of hydraulic fluid through the lock line 216 toward the pilot blocks 210. Similarly, the operator may provide an unlock input to an unlock input device 222, which may cause a flow of hydraulic fluid through the unlock line 218 toward the pilot blocks 210.

As noted herein, each pilot block 210 is actuated (e.g. opened) in response to sufficient pressure in the respective close line 202. Accordingly, the flow of hydraulic fluid may flow through the lock line 216 to actuate respective lock members while (e.g., as long as; only while) there is sufficient pressure in the respective close line 202. Further, as noted herein, the sufficient pressure corresponds to an amount of pressure that is applied to (e.g., effective to) adjust the respective BOP 42 to the closed configuration 58. Thus, the flow of hydraulic fluid may flow through the lock line 216 to actuate respective lock members while (e.g., as long as; only while) the respective BOP 42 is in the closed configuration 58. For example, upon the close input at the first close input device 206A, pressure may be applied through the first close line 202A. Once the pressure within the first close line 202A drives the first BOP 42A to the closed configuration 58, the pressure may build within the first close line 202A as shown by arrow 224 and actuate the first pilot block 210A. Thus, the flow of hydraulic fluid may flow through the lock line 216 as shown by arrow 226 to drive the respective lock members for the first BOP 42A to lock the first BOP 42A in the closed configuration 58.

Advantageously, the first BOP 42A may be locked independently of the second BOP 42B and the third BOP 42C due to presence of the respective pilot blocks 210 that are each coupled to the respective close lines 202. For example, in FIG. 6, because the second close input device 206B and the third close input device 206C are not selected at the controller 112, there is not sufficient pressure present in the second close line 202B and the third close line 202C. Thus, the second pilot block 210B and the third pilot block 210C are not actuated and block the flow of the hydraulic fluid through the respective check valves 212, 214 of the second pilot block 210B and the third pilot block 210C.

Accordingly, even though the operator provided the lock input to the lock input device 220, the flow of the hydraulic fluid in the lock line 216 does not travel across the second pilot block 210B and the third pilot block 210C and does not reach the respective lock assemblies 90 for the second BOP 42B and the third BOP 42C. As described herein, this may provide various advantages, such as blocking the respective lock assemblies 90 from driving the second BOP 42B and the third BOP 42C to the closed configuration 58 (e.g., in absence of respective close inputs to the second close input device 206B and the third close input device 206C).

FIG. 7 is a schematic diagram of an embodiment of the lock system 88, wherein the lock system 88 unlocks at least one BOP 42 of the BOP stack 16. FIG. 7 includes various components and features shown and described with reference to FIG. 6. As noted herein, each pilot block 210 is actuated in response to sufficient pressure in the respective close line 202. Accordingly, the flow of hydraulic fluid may flow through the unlock line 218 as shown by arrows 228 to actuate respective lock members while (e.g., as long as; only while) there is sufficient pressure in the respective close line 202. Thus, the flow of hydraulic fluid may flow through the unlock line 218 to actuate respective lock members while (e.g., as long as; only while) the respective BOP 42 is in the closed configuration 58. This may block unintentional unlocking of the BOPs 42, such as to certain BOPs 42 where the pressure to close is no longer applied (e.g., where the respective lock members hold and lock the BOP 42 in the closed configuration 58, without further or continuous pressure through the close line 202). Advantageously, the first BOP 42A may be unlocked independently of the second BOP 42B and the third BOP 42C due to presence of the respective pilot blocks 210 that are each coupled to the respective close lines 202.

FIG. 8 is a schematic diagram of an embodiment of the lock system 88, wherein the lock system 88 locks at least one BOP 42 of the BOP stack 16 and includes at least one common line 230 (e.g., lock-unlock common line). The lock system 88 and the BOP stack 16 of FIG. 8 may include any of the features of the lock system 88 of FIGS. 6 and 7. However, for each BOP 42, the lock system 88 of FIG. 8 includes a respective common line 230 to facilitate corresponding operation (e.g., both lock or both unlock) of a first lock member and a second lock member (e.g., within respective lock assemblies 90 positioned on opposite sides of the BOP 42).

As shown, the BOP stack 16 includes the first BOP 42A, the second BOP 42B, and the third BOP 42C. However, it should be appreciated that the BOP stack 16 may include any number of BOPs 42. Each BOP 42 is associated with a respective close line 202, such as the first close line 202A for the first BOP 42A, the second close line 202B for the second BOP 42B, and the third close line 2020 the third BOP 42C. Additionally, each BOP 42 is associated with a respective open line 204, such as the first open line 204A for the first BOP 42A, the second open line 204B for the second BOP 42B, and the third open line 204C the third BOP 42C.

The controller 112 may include the input devices 206, 208. As shown in FIG. 8, the first BOP 42A is in the closed configuration 58, while the second BOP 42B and the third BOP 42C are in the open configuration 56. Further, each BOP 42 is associated with a respective pilot block 210, such as the first pilot block 210A for the first BOP 42A, the second pilot block 210B for the second BOP 42B, and the third pilot block 210C for the third BOP 42C. Each pilot block 210 is actuated via pressure applied via a respective close line 202.

Each pilot block 210 also includes a respective first check valve 212 that is fluidly coupled to the lock line 216 and a respective second check valve 214 that is fluidly coupled to an unlock line 218. In operation, the operator may provide the lock input to the lock input device 220 and the unlock input to the unlock input device 222. As noted herein, each pilot block 210 is actuated (e.g. opened) in response to sufficient pressure in the respective close line 202. Accordingly, the flow of hydraulic fluid may flow through the lock line 216 to actuate respective lock members while (e.g., as long as; only while) there is sufficient pressure in the respective close line 202.

For example, upon the close input at the first close input device 206A, pressure may be applied through the first close line 202A. Once the pressure within the first close line 202A drives the first BOP 42A to the closed configuration 58, the pressure may build within the first close line 202A as shown by arrow 224 and actuate the first pilot block 210A. Thus, the flow of hydraulic fluid may flow through the lock line 216 as shown by arrow 226 to drive a first lock member of the first BOP 42A (e.g., the first lock member of a respective lock assembly 90, such as a rotary lock right assembly in FIG. 8). Further, as the first lock member moves to the lock position, a respective flow of hydraulic fluid may flow through a respective common line 230 as shown by arrow 234 to a second lock member of the first BOP 42A (e.g., the second lock member of a respective lock assembly 90, such as a rotary lock left assembly in FIG. 8). In this way, both the first lock member and the second lock member may move to lock the first BOP 42A in the closed configuration 58. The common line 230 fluidly couples an unlock chamber or portion for one of the lock members (e.g., to cause an unlocking operation) to a lock chamber or portion for another one of the lock members (e.g., to cause a locking operation). Accordingly, the common line 230 enables efficient, corresponding operation of the lock members of the first BOP 42A.

FIG. 9 is a schematic diagram of an embodiment of the lock system 88 of FIG. 12, wherein the lock system 88 unlocks at least one BOP 42 of the BOP stack 16. FIG. 9 includes various components and features shown and described with reference to FIG. 8. As noted herein, each pilot block 210 is actuated in response to sufficient pressure in the respective close line 202. Accordingly, the flow of hydraulic fluid may flow through the unlock line 218 as shown by the arrow 228 to actuate respective lock members while (e.g., as long as; only while) there is sufficient pressure in the respective close line 202.

For example, the pressure within the first close line 202A holds the first BOP 42A in the closed configuration 58 and actuates the first pilot block 210A. Thus, the flow of hydraulic fluid may flow through the unlock line 218 as shown by arrow 228 to drive the second lock member of the first BOP 42A. Further, as the second lock member moves to the unlock position, a respective flow of hydraulic fluid may flow through the respective common line 230 as shown by arrow 236 to the first lock member of the first BOP 42A. In this way, both the first lock member and the second lock member may move to unlock the first BOP 42A and enable adjustment of the first BOP 42A from the closed configuration 58 (e.g., upon subsequent selection of the first open input device 208A). Advantageously, the first BOP 42A may be unlocked independently of the second BOP 42B and the third BOP 42C due to presence of the respective pilot blocks 210 that are each coupled to the respective close lines 202.

FIG. 10 is a schematic diagram of an embodiment of the pilot block 210 that includes a flow regulator 240 (e.g., flow regulator assembly). It should be appreciated that each pilot block 210, such as each pilot block 210 shown in FIGS. 6-9, may include features shown and described with reference to FIG. 10. As shown, the pilot block 210 includes a first unidirectional flow regulator 242 that is fluidly coupled to the lock line 216 and a second unidirectional flow regulator 244 that is fluidly coupled to the unlock line 218. As shown, the first unidirectional flow regulator 242 and the second unidirectional flow regulator 244 include a respective orifice 246 (e.g., a variable or adjustable orifice) and a reverse check valve 248. The first unidirectional flow regulator 242 and the second unidirectional flow regulator 244 may operate to adjust the flow of hydraulic fluid to the lock assemblies (e.g., the lock assemblies 90 of FIGS. 2-9), such as to enable operation of hydraulic motors with appropriate parameters (e.g., torque).

FIG. 11 is a perspective top view of an embodiment of the BOP 42 with the pilot block 210 coupled to the body 70 of the BOP 42. For example, the pilot block 210 may be coupled to the body 70 of the BOP 42 via one or more fasteners (e.g., threaded fasteners, such as bolts). In an embodiment, the pilot block 210 may be coupled to a lateral side of the body 70 of the BOP 42 (e.g., extending from a surface of the body 70 of the BOP 42 along the lateral axis 34) and/or may be positioned between the lock assemblies 90 along the longitudinal axis 32. In FIG. 11, the lock system 88 includes the lock line 216, the unlock line 218, and the common line 230. However, it should be appreciated that the lock system 88 may include other configurations (e.g., without the common line 230, such as configurations shown in FIGS. 6 and 7).

Additionally, in FIG. 11, the pilot block 210 may include the flow regulator 240 of FIG. 10. However, it should be appreciated that the pilot block 210 may instead not include the flow regulator 240 of FIG. 10 (e.g., be devoid of the flow regulator 240 of FIG. 10). In some such cases, a separate flow regulator may be positioned along the lock line 216 and/or the unlock line 218.

FIG. 12 is a perspective top view of an embodiment of the pilot block 210. In FIG. 12, a pilot block housing 250 may support (e.g., house; surround) the two pilot operated check valves (e.g., check valves 212, 214 of FIGS. 6-9) and/or the flow regulator (e.g., the flow regulator 240 of FIG. 10). For example, the flow regulator may include a cartridge 252 with two flow regulators (e.g., the unidirectional flow regulators 242, 244 of FIG. 10), and the cartridge may be supported within the pilot block housing 250. Additionally, as shown, the pilot block 210 includes multiple connectors that extend from the pilot block housing 250, such as to fluidly couple to the lock line 216, the unlock line 218, and the close line 202 (see FIGS. 6-10).

FIG. 13 is a perspective top view of an embodiment of the pilot block 210. In certain embodiments, particularly when the pilot block 210 includes the flow regulator (e.g., the flow regulator 240 of FIG. 10), it may be desirable to provide additional shielding about the pilot block 210. For example, a fire shield 260 may be coupled to (e.g., included as part of; fastened to) the pilot block housing 250 (FIG. 12) to provide protection to components within the pilot block housing 250, such as to protect the two pilot operated check valves 212, 214 and/or the flow regulator 240 and/or enable operation of the two pilot operated check valves 212, 214 and/or the flow regulator 240 even when certain conditions (e.g., fire; extreme temperature) are present around the pilot block housing 250 (see FIGS. 6-12). The fire shield 260 may include multiple structures 262 (e.g., plates) that couple (e.g., fix; fasten) to the pilot block housing 250, such as via one or more fasteners 264 (e.g., threaded fasteners, such as bolts). The fire shield 260 may be formed from any suitable materials. It should be appreciated that the fire shield 260 may be integrally formed (e.g., one-piece) with the pilot block housing 250, such as via additive manufacturing techniques to layer the fire shield 260 onto the pilot block housing 250 and/or by forming the pilot block housing 250 from certain materials with fire shielding properties.

FIG. 14 is flow diagram of a method 300 of operating a lock system, such as the lock system 88, in accordance with an embodiment of the present disclosure. It should be appreciated that certain steps of the method 300 may be performed by control components (e.g., the controller 112 and/or the one or more pilot blocks 210). It should be appreciated that steps may be omitted, steps may be added, and/or steps may be carried out in any suitable order.

In block 302, the method 300 includes, in response to a respective close command for a BOP, initiating a flow of a hydraulic fluid through a close line to adjust the BOP to a closed configuration. In block 304, the method 300 includes, in response to a lock command, initiating a flow of hydraulic fluid through a lock line toward a pilot block. In block 306, the method 300 includes actuating, via target pressure in the close line, the pilot block to enable the flow of hydraulic fluid through the lock line, across the pilot block, and to at least one ock assembly of the BOP. Accordingly, the lock system may lock the BOP in the closed configuration.

In certain embodiments, the BOP may include a first lock assembly with a first lock member and a second lock assembly with a second lock member. The first lock member may be configured to selectively engage and lock a first ram of the first BOP, and the second lock member may be configured to selectively engage and lock a second ram of the first BOP. In certain embodiments, the lock line may be fluidly coupled to both the first lock assembly and the second lock assembly, and thus enable the flow of hydraulic fluid to drive (e.g., directly drive) both the first lock member and the second lock member. Alternatively, the lock line may be fluidly coupled to the respective lock chamber for the first lock member, and a common line may be utilized to direct fluid from the first lock member to the second lock member to thereby enable the flow of hydraulic fluid to drive (e.g., directly and indirectly drive) both the first lock member and the second lock member.

In block 308, the method 300 includes blocking the flow of hydraulic fluid through the lock line to an additional BOP without an additional close command for the additional BOP. In this way, no lock assembly for the second BOP may be actuated to perform a lock function without the additional close command for the additional BOP, and thus without the additional BOP in the closed configuration.

While the method 300 relates to steps to provide the lock function, it should be appreciated that the method 300 may additionally or alternatively include steps to provide an unlock function. For example, the method may include, in response to an unlock command, initiating a flow of hydraulic fluid through an unlock line toward the pilot block. In such cases, the method includes actuating, via the target pressure in the close line, the pilot block to enable the flow of hydraulic fluid through the unlock line, across the pilot block, and to the at least one lock assembly of the BOP. Accordingly, at least the lock assembly may unlock the BOP in the closed configuration, to thereby enable transition of the BOP to an open configuration upon a first open command. In such cases, the method also includes blocking the flow of hydraulic fluid through the unlock line to the additional BOP without the additional close command for the additional BOP. In this way, no lock assembly for the additional BOP may be actuated to perform the unlock function without the additional close command for the additional BOP, and thus without the additional BOP in the closed configuration.

It should be appreciated that hydraulic fluid may be provided or supplied from a hydraulic fluid source (e.g., supply; tank; reservoir). For example, the close lines, the open lines, the lock lines, and the unlock lines may be fluidly coupled to the hydraulic fluid source. Further, as used herein, the hydraulic fluid source may refer to one or more hydraulic fluid sources (e.g., one or more supplies; one or more tanks; one or more reservoirs; common or different sources). Additionally, it should be appreciated that the pilot block may include a flow regulator, or separate flow regulators may be positioned along the lock line and/or the unlock line. For example, with reference to FIG. 8 to facilitate discussion, a respective separate regulator may be in-line with the lock line 216 between the pilot block 210 and a respective lock assembly 90, such as in or near a portion 243 of the lock line 216 shown in FIG. 8. Further, a respective separate flow regulator may be in-line with the unlock line 218 and between the pilot block 210 and a respective lock assembly 90, such as in or near a portion 245 of the lock line 216 shown in FIG. 8). It should be appreciated that any of the features illustrated and described with respect to FIGS. 1-14 may be combined in any suitable manner. 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 to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the following appended claims.

PILOT BLOCK SYSTEM TO LOCK A BLOWOUT PREVENTER STACK

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