US20170191334A1

US20170191334A1 - Systems and methods for engaging subsea equipment

Info

Publication number: US20170191334A1
Application number: US14/986,004
Authority: US
Inventors: Andrew Jaffrey
Original assignee: Cameron International Corp
Current assignee: Cameron International Corp
Priority date: 2015-12-31
Filing date: 2015-12-31
Publication date: 2017-07-06

Abstract

A system for landing a subsea component includes a retention assembly configured to be coupled to the subsea component, the retention assembly including a first connector, a cable extending between the connector and a tensioning assembly, and a releasable lock configured to selectably actuate the tensioning assembly between a locked position and an unlocked position, wherein, when the tensioning assembly is in the unlocked position, a tensioning force is applied to the cable, and an anchoring assembly configured to anchor to a sea floor, the anchoring assembly including a second connector configured to be coupled to the first connector of the retention assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND

Hydrocarbon drilling systems utilize drilling fluid or mud for drilling a wellbore in a subterranean earthen formation. In some offshore applications, a conductor housing is installed through a temporary guidebase disposed on the sea floor, where the conductor housing is coupled to casing conductor that extends into the sea floor. A permanent guidebase follows the installation of the conductor housing in the sea floor, and a wellhead housing is then installed within the conductor housing disposed on the sea floor. Once the conductor and wellhead housings are secured on the sea floor, a blowout preventer (BOP) stack is secured to the wellhead housing for controlling the flow of fluid into and out of the wellbore. Following the installation of the BOP stack, a lower marine riser package (LMRP) is secured to the BOP stack for providing a conduit for drilling fluids between a drilling vessel at the surface and the wellhead disposed on the sea floor. Each of the components described above, including the BOP stack and LMRP, may be installed at the sea floor by lowering the components from a drilling vessel or semi-submersible drilling rig disposed at the surface. Specifically, the components may be suspended from a marine riser, cable, or other component and lowered towards the sea floor. In some applications, the drilling vessel includes a heave compensation system for maintaining the vertical position (e.g., the vertical distance to the sea floor) of the suspended component as the drilling vessel is displaced vertically at the surface due to waves or other turbulence.

SUMMARY

An embodiment of a system for landing a subsea component comprises a retention assembly configured to be coupled to the subsea component, the retention assembly comprising a first connector, a cable extending between the connector and a tensioning assembly, and a releasable lock configured to selectably actuate the tensioning assembly between a locked position and an unlocked position, wherein, when the tensioning assembly is in the unlocked position, a tensioning force is applied to the cable, and an anchoring assembly configured to anchor to a sea floor, the anchoring assembly comprising a second connector configured to be coupled to the first connector of the retention assembly. In some embodiments, the retention assembly further comprises a locking assembly configured to allow the passage of the cable through the locking assembly in a first direction towards the retention assembly, and restrict passage of the cable through the locking assembly in a second direction away from the retention assembly. In some embodiments, the tensioning assembly comprises a cylinder configured to couple to the subsea component, and a piston slidably disposed in the cylinder and coupled to an end of the cable, wherein the cylinder includes an open end for providing fluid communication between a first end of the piston and the subsea environment. In certain embodiments, when the tensioning assembly is in the locked position, the releasable lock physically engages the piston to restrict the piston from being displaced through the cylinder, and when the tensioning assembly is in the unlocked position, the piston is displaced through the cylinder in response to fluid pressure acting against the first end of the piston. In some embodiments, in response to the piston being displaced through the cylinder, the cable is passed through the locking assembly to reduce slack in the cable. In some embodiments, the anchoring assembly comprises a first ring concentrically disposed in a second ring, and a third ring, wherein the first and second rings are each concentrically disposed in the third ring, wherein the first ring is pivotally coupled to the second ring such that the first ring is configured to pivot about a first axis relative to the second ring, and wherein the second ring is pivotally coupled to the third ring such that the second ring is configured to pivot about a second axis relative to the third ring. In certain embodiments, the anchoring assembly comprises a damper configured to damp forces applied to the subsea component when the first connector is coupled to the second connector.
An embodiment of a system for landing a subsea component comprises a first subsea component, a retention assembly coupled to the first subsea component, the retention assembly comprising a first connector, a cable extending between the connector and a tensioning assembly, wherein the tensioning assembly is configured to apply a tensioning force to the cable, a locking assembly configured to allow the passage of the cable through the locking assembly in a first direction towards the retention assembly, and restrict passage of the cable through the locking assembly in a second direction away from the retention assembly, and an anchoring assembly configured to anchor to a sea floor, the anchoring assembly comprising a second connector for coupling with the first connector of the retention assembly. In some embodiments, the retention assembly further comprises a releasable lock configured to selectably actuate the tensioning assembly between a locked position and an unlocked position, wherein, when the tensioning assembly is in the unlocked position, a tensioning force is applied to the cable in response to a pressure force applied against the tensioning assembly from the surrounding environment. In some embodiments, the tensioning assembly comprises a cylinder coupled to the subsea component, and a piston slidably disposed in the cylinder and coupled to an end of the cable, wherein the cylinder has an open end for providing fluid communication between a first end of the piston and the subsea environment. In certain embodiments, when the tensioning assembly is in the locked position, the releasable lock physically engages the piston to restrict the piston from being displaced through the cylinder, and when the tensioning assembly is in the unlocked position, the piston is displaced through the cylinder in response to fluid pressure acting against the first end of the piston. In certain embodiments, in response to the piston being displaced through the cylinder, the cable is passed through the locking assembly to reduce slack in the cable. In some embodiments, the anchoring assembly comprises a first ring concentrically disposed in a second ring, and a third ring, wherein the first ring and the second ring are each concentrically disposed in the third ring, wherein the first ring is pivotally coupled to the second ring such that the first ring is configured to pivot about a first axis relative to the second ring, and wherein the second ring is pivotally coupled to the third ring such that the second ring is configured to pivot about a second axis relative to the third ring. In some embodiments, the system further comprises a detector configured to detect a distance between the first subsea component and a second subsea component, and a controller in signal communication with the detector, wherein the controller is configured to adjust a tensioning force applied to the cable in response to a signal transmitted to the controller from the detector.
An embodiment of a method of landing a subsea component comprises deploying a subsea component in a subsea environment, lowering the subsea component to a target location near a sea floor, coupling a cable extending from a retention assembly coupled to the subsea component to an anchoring assembly, and actuating a tensioning assembly of the retention assembly to apply a tensioning force to the cable to guide the subsea component towards the anchoring assembly. In some embodiments, the method further comprises passing the cable through a locking assembly to reduce slack in the cable. In some embodiments, the method further comprises restricting passing the cable through the locking assembly in the second direction in response to a force applied against the subsea component. In certain embodiments, the method further comprises damping a force applied against the subsea component after coupling the cable. In certain embodiments, the method further comprises rotating a connector of the anchoring assembly in a gimbal assembly. In some embodiments, the method further comprises utilizing a controller to automatically adjust a tensioning force to the cable in response to a threshold level of lateral gap between the subsea component and the target location.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of exemplary embodiments, reference will now be made to the accompanying drawings in which:

FIG. 1 is a schematic view of an embodiment of a drilling system showing a BOP stack in a first position in accordance with principles disclosed herein;

FIG. 2 is a cross-sectional view of a retention assembly of the drilling system of FIG. 1 in accordance with principles disclosed herein;

FIG. 3A is a schematic view of a locking assembly of the drilling system of FIG. 1 in a first position in accordance with principles disclosed herein;

FIG. 3B is a schematic view of the locking assembly of FIG. 3A in a second position;

FIG. 4A is a schematic view of an anchoring assembly in accordance with principles disclosed herein;

FIG. 4B is a top view of the anchoring assembly of FIG. 4A;

FIG. 5 is a schematic view of the drilling system of FIG. 1 in a second position;

FIG. 6 is a schematic view of the drilling system of FIG. 1 in a third position;

FIG. 7 is a schematic view of the drilling system of FIG. 1 in a fourth position;

FIG. 8 is an embodiment of a method for landing a subsea component in accordance with principles disclosed herein; and

FIG. 9 is a schematic view of another embodiment of a drilling system including a BOP stack in accordance with principles disclosed herein.

DETAILED DESCRIPTION

In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the disclosed embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present disclosure is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results.
Unless otherwise specified, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Any use of any form of the terms “connect”, “engage”, “couple”, “attach”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings.
FIG. 1 is a schematic diagram illustrating an embodiment of a drilling system 10. In an embodiment, drilling system 10 comprises a system for landing a subsea component. The drilling system 10 can be configured to extract various minerals and natural resources, including hydrocarbons (e.g., oil and/or natural gas), or configured to inject substances into a sea floor 3 and a subterranean earthen formation 5 via a well or wellbore 7. In this embodiment, drilling system 10 generally includes a semi-submersible drilling rig 12 disposed at a surface or waterline 9, a wellhead 18 secured to the sea floor 3 via a casing conductor 20 that extends into the formation 5, a remotely operated underwater vehicle (ROV) 22 disposed below the waterline 9 and including an actuatable arm or gripper 24 and a camera or image sensor 28, a subsea component or blowout preventer (BOP) assembly 100 disposed beneath the waterline 9, and a plurality of anchoring assemblies 160 anchored to the sea floor 3 and disposed about the wellhead 18. In FIG. 1 BOP assembly 100 is disposed near the waterline 9 after being lowered through the waterline 9 as BOP assembly 100 descends towards the sea floor 3. In this embodiment, ROV 22 is connected to the drilling rig 12 via a cable 25 that supplies power and real-time signal communication between ROV 22 and drilling rig 12. However, in other embodiments, ROV 22 may be untethered from drilling rig 12 and comprising an internal power supply and an antenna for wirelessly transmitting signals to the drilling rig 12. In still further embodiments, ROV 22 may comprise an autonomous or semi-autonomous vehicle.
In this embodiment, drilling rig 12 includes a rig floor 14 and a derrick 17 extending from floor 14 that supports a marine riser 16 coupled to the BOP assembly 100 as the riser 16 and BOP assembly 100 are lowered from the waterline 9 to the wellhead 18 disposed at the sea floor 3. In this embodiment, BOP assembly 100 has a central or longitudinal axis 105 and generally includes a BOP frame 102 coupled to a lower end of riser 16, a BOP 104 disposed within BOP frame 102, and a plurality of retention assemblies 110 coupled to the BOP frame 110. As BOP assembly 100 is lowered towards sea floor 3, transient forces 13 are applied to BOP assembly 100 from subsea currents, jerks or transient forces from riser 16, and other forces, which cause BOP assembly 100 to sway or move laterally and angularly as BOP assembly 100 is lowered vertically towards sea floor 3. Although in this embodiment drilling system 10 includes drilling rig 12 and marine riser 16, in other embodiments, drilling system 10 may include a mono-hull drilling vessel including a crane supporting a cable from which BOP assembly 100 is suspended, or other drilling vessels or rig systems.
In an embodiment, drilling vessel 12 includes a heave compensating system for controlling the vertical position respective sea floor 3 of BOP assembly 100. Specifically, the heave compensating system of drilling rig 12 maintains the vertical position of BOP assembly 100 as the vertical position of drilling rig 12 rises and falls in response to wave action at the waterline 9. Although the heave compensating system of drilling rig 12 is configured to maintain the vertical position of BOP assembly 100 relative sea floor 3, the heave compensating system is not configured to maintain the lateral and angular position of BOP assembly 100 as transient forces act against BOP assembly 100. Thus, transient forces applied to BOP assembly 100 cause longitudinal axis 105 of BOP assembly 100 to become laterally misaligned with a longitudinal axis 15 of wellhead 18, resulting in a lateral gap 107 between longitudinal axis 105 and longitudinal axis 15.
Retention assemblies 110 are configured to releasably couple with anchoring assemblies 160 and thereby guide BOP assembly 100 into engagement with wellhead 18 such that BOP 104 may couple with wellhead 18 to provide a sealed flowpath between an internal throughbore of BOP 104 and a throughbore of casing conductor 20. Particularly, retention assemblies 110 are configured to releasably couple with anchoring assemblies 160 to align longitudinal axis 105 of BOP assembly 100 with longitudinal axis 15 of wellhead 18 such that longitudinal axis 105 is disposed substantially coaxial with longitudinal axis 15. In this embodiment, each retention assembly 110 generally includes a tensioning or cylinder assembly 112, a locking assembly 130, and a first or male connector 158. In this embodiment, four retention assemblies 110 are included in BOP assembly 100 with a retention assembly 110 coupled to each corner of BOP frame 102. However, in other embodiments varying numbers of retention assemblies 110 may be coupled to BOP frame 102 or other components of BOP assembly 100 in various configurations.
Referring to FIGS. 1 and 2, cylinder assembly 112 includes an elongate cylinder 114 having a first or upper end 114 a and a second or lower end 114 b, where lower end 114 b is disposed vertically (relative sea floor 3) below upper end 114 a. Lower end 114 b of cylinder 114 includes a port 116 providing for fluid communication between an internal volume 113 of cylinder 114 and the surrounding subsea environment. Cylinder assembly 112 also includes a piston 118 slidably disposed within cylinder 114 and includes an annular seal 120 that is disposed in an outer surface thereof for sealably engaging an inner surface of cylinder 114. Sealing engagement between annular seal 120 and the inner surface of cylinder 114 divides volume 113 into an upper volume or chamber 113 a extending between the upper end 114 a of cylinder 114 and piston 118, and a lower volume or chamber 113 b extending between piston 118 and the lower end 114 b.
In this embodiment, upper chamber 113 a is filled with a compressible fluid or gas (e.g., air), while lower chamber 113 b is in fluid communication with the surrounding subsea environment. A releasable lock 118 a extends through cylinder 114 and into upper chamber 113 a to physically engage an upper end of piston 118 to releasably lock piston 118 in a lower or first position proximal lower end 114 b of cylinder 114. In this embodiment, releasable lock 118 a comprises a release pin; however, in other embodiments, releasable lock may comprise other types of releasable locks known in the art. In this configuration, hydrostatic pressure of the sea water acts against a lower end of piston 118 while lock 118 a holds piston 118 into the first position and prevents piston 118 from being displaced upwards through cylinder 114, compressing the fluid disposed in upper chamber 113 a. Also, the lower end of piston 118 includes a connector 122 coupled to an upper end of a cable or hawser 124 that extends through port 116.
Disposed directly beneath the lower end 114 b of each cylinder 114 is a locking assembly 130. Each locking assembly 130 is configured to allow for the passage of hawser 124 therethrough in a first direction, while selectably restricting the passage of hawser 124 through locking assembly 130 in a second or opposing direction. Particularly, each locking assembly 130 is configured to allow for the passage of hawser 124 in an upwards direction towards cylinder 114 while restricting the passage of hawser 124 in a downwards direction away from cylinder 114.
Referring to FIGS. 1-3B, in this embodiment each locking assembly 130 generally includes a mounting member 132, a clamping block 134 affixed to the mounting member 132, a pivot arm 140 pivotally coupled to mounting member 132, and a guide member 156. Mounting member 132 is mounted or coupled to BOP frame 102 of BOP assembly 100 such that locking assembly 130 is disposed directly beneath the lower end 114 b of cylinder 114. Clamping block 134 is affixed to mounting member 132 and includes a curved or convex engagement surface 136 for frictionally engaging hawser 124. Pivot arm 140 is pivotally coupled to mounting member 132 at pivot joint 142 and includes an engagement surface 144 configured to frictionally engage hawser 124 and a handle 146 distal engagement surface 144 and configured to be actuatable by the gripper 24 of ROV 22. In this arrangement, a passage or pathway 148 is formed between the engagement surface 136 of clamping block 134 and the engagement surface 144 of pivot arm 140.
Pivot arm 140 includes a first or locked position shown in FIG. 3A that allows the passage of hawser 124 in a first or upward direction 150 (i.e., towards cylinder 114) through passage 148 and restricts the passage of hawser 124 in a second or downward direction 152 (i.e., away from cylinder 114) through passage 148. Passage of hawser 124 is allowed in the upward direction 150 while restricted in the downward direction 152 due to the offset position of pivot joint 142 relative engagement surface 144. Particularly, when hawser 124 passes in the upward direction 150, frictional engagement between hawser 124 and engagement surface 144 causes pivot arm 140 to pivot in a first or clockwise direction, expanding the width of passage 148. However, when hawser 124 passes in the downward direction 152, frictional engagement between hawser 124 and engagement surface 144 causes pivot arm 140 to pivot in a second or counterclockwise direction, reducing the width of passage 148 and thereby causing engagement surfaces 136 and 144 to grapple or grab hawser 124, restricting further passage of hawser 124 in the downward direction 152. While in this embodiment pivot arm 140 is actuated via gripper 24 of ROV 22, in other embodiments, pivot arm 140 may be actuated between the locked and unlocked positions via the transmission of a remote signal transmitted from the surface to an antenna in signal communication with an electronically, hydraulically, pneumatically or otherwise actuatable pivot arm of locking device 130.
Pivot arm 140 also includes a second or unlocked position shown in FIG. 3B where engagement surface 144 is disposed distal hawser 124, thereby allowing the passage of hawser 124 in both the upward direction 150 and the downward direction 152. In this embodiment, pivot arm 140 is biased into the first position via a biasing member (not shown). In this arrangement, pivot arm 140 may be actuated from the locked position shown in FIG. 3A to the unlocked position shown in FIG. 3B via the grabber 24 of ROV 22. In this embodiment, each locking assembly 130 also includes a guide member 156 affixed to BOP housing 102 and disposed directly beneath mounting member 132, where guide member 156 includes an aperture extending therethrough to guide hawser 124 towards passage 148. In this configuration, guide member 156 restricts hawser 124 from becoming tangled within or slipping free from passage 148. Although in the embodiment of FIGS. 3A and 3B, locking devices 130 comprise base plate 132 and pivot arm 140, in other embodiments, locking devices 130 may comprise other mechanisms configured for allowing the passage of hawser 124 in the upwards direction 150 while restricting the passage of hawser 150 in the downwards direction 152.
As shown particularly in FIG. 1, the lower end of hawser 124 is coupled to male connector 158. As will be discussed further herein, male connector 158 is configured to releasably connect to a female connector of a corresponding anchoring assembly 160, forming a releasable connection between each retention assembly 110 and corresponding anchoring assembly 160. In this embodiment, male connector 158 comprises the male connector of a subsea mooring or ball and taper connector, such as the Ballgrab® Subsea mooring Connector (SMC) provided by First Subsea Ltd located at Lune Industrial Estate, New Quay Road, Lancaster, Lancashire, LA1 5QP, United Kingdom. However, in other embodiments, male connector 158 may comprise other types of male connectors known in the art configured for usage in subsea environments, such as the quick release lifting pins offered by Automotion Components Ltd., Alexia House, Little Mead Industrial Estate, Cranleigh, Surrey, GU6 8NE, UK, or other components known in the art such as shackles that may be secured to eyes in the hawsers 124. Also, as BOP assembly 100 is lowered towards sea floor 3, the length of hawser 124 may be coiled to prevent hawser 124 from becoming tangled with other components of BOP assembly 100. Prior to connecting male connector 158 with a corresponding female connector of anchoring assembly 160, as will be discussed further herein, grabber 24 of ROV 22 may release or uncoil the length of hawser 124 from BOP assembly 100.
Referring to FIGS. 1, 4A, and 4B, each anchoring assembly 160 is configured to releasably couple with a corresponding retention assembly 110 to couple BOP assembly 100 to the sea floor 3 and guide BOP assembly 100 into engagement with wellhead 18. Particularly, in this embodiment, four anchoring assemblies 160 are disposed about wellhead 18 corresponding with the four retention assemblies 110 coupled to BOP frame 102. However, in other embodiments, BOP assembly 100 may only include a single retention assembly 110. In this arrangement, when longitudinal axis 105 of BOP assembly 100 aligns with longitudinal axis 15 of wellhead 18, each anchoring assembly 160 longitudinally or vertically aligns with a corresponding retention assembly 110, as will be discussed further herein. In this embodiment, each anchoring assembly 160 generally includes a support frame 162, a gimbal assembly 164 physically supported by support frame 162, and a female connector assembly 180 coupled to gimbal assembly 164. Support frame 162 is anchored or coupled to the sea floor 3 and is configured to physically support gimbal assembly 164 and female connector assembly 180. In this embodiment, support frame 162 comprises a plurality of legs 162 a extending from gimbal assembly 180 to the sea floor 3.
Gimbal assembly 164 of anchoring assembly 160 is configured to provide for the rotation of female connector assembly 180 about multiple independent axes relative support frame 162. In this arrangement, female connector assembly 180 may axially align with tension forces applied to hawser 124 once male connector 158 has been inserted into and coupled with female connector assembly 180. In this embodiment, the gimbal assembly 164 of each anchoring assembly 160 generally includes a first or inner ring 166, a pair of first or inner coupling pins 168, a second or intermediate ring 170, a pair of second or outer coupling pins 172, and a third or outer ring 174 coupled to an upper end of support frame 162. Inner coupling pins 168 pivotally couple inner ring 166 with intermediate ring 170, providing for rotation of inner ring 166 about a first axis 169 relative intermediate ring 170. Also, outer coupling pins 172 pivotally couple intermediate ring 170 with outer ring 174, providing for rotation of intermediate ring 170 about a second axis 171 relative outer ring 174. In this arrangement, inner ring 166 is pivotal about both first axis 169 and second axis 171 relative outer ring 174 and support frame 162. Further, first axis 169 is disposed orthogonal to second axis 171.
Female connector assembly 180 is coupled to inner ring 166, thus allowing female connector assembly 180 to pivot about first axis 169 and second axis 171 relative support frame 162. The female connector assembly 180 of each anchoring assembly 160 is configured to releasably couple with a male connector 158 of a corresponding retention assembly 110. Female connector assembly 180 is also configured to dampen forces transmitted to BOP support assembly 100 from anchoring assemblies 160 once BOP assembly 100 has been coupled to anchoring assemblies 160.
In this embodiment, each female connector assembly 180 generally includes a cylinder 182, a piston 190 disposed in cylinder 182, and a female connector 194 coupled to an upper end of piston 190. Cylinder 182 has a first or upper end 182 a, a second or lower end 182 b, and an internal volume 184 disposed therein. The upper end 182 a of cylinder 182 includes a centrally disposed aperture 186 and the lower end 182 b includes a plurality of tuned ports 188. Piston 190 includes an annular seal 192 disposed in an outer surface thereof for sealingly engaging an inner surface of cylinder 182. The sealing engagement provided by annular seal 192 divides internal volume 184 into a first or upper chamber 184 a extending between upper end 182 a and the upper end of piston 190, and a second or lower chamber 184 b extending between a lower end of piston 190 and the lower end 182 b of cylinder 182. Female connector 194 couples to the upper end of piston 190 and extends through aperture 186 at the upper end 182 a of cylinder 182. An inner surface of aperture 186 for sealingly engaging an outer surface of female connector 194, thereby restricting fluid communication between upper chamber 184 a and the surrounding subsea environment. In this embodiment, upper chamber 184 a is filled with a compressible fluid, such as air. Lower chamber 184 b of cylinder 182 is in fluid communication with the surrounding subsea environment via ports 188, and is thus filled with sea water.
In this embodiment, female connector 194 comprises the corresponding female connector of a subsea mooring or ball and taper connector, such as the Ballgrab® Subsea mooring Connector (SMC) provided by First Subsea Ltd located at Lune Industrial Estate, New Quay Road, Lancaster, Lancashire, LA1 5QP, United Kingdom. However, in other embodiments, female connector 194 may comprise other types of male connectors known in the art configured for usage in subsea environments, such as the quick release lifting pins and/or shackles described above with respect to male connector 158. Also, female connector 194 includes a radially flanged guided member 194 a at an upper end thereof for guiding the male connector 158 of a corresponding retention assembly 110 into engagement with female connector 194. In this embodiment, male connector 158 may be releasably coupled or secured to female connector 194 by axially inserting male connector 158 into female connector 194 regardless of the angular orientation between male connector 158 and female connector 194. Once male connector 158 is inserted into female connector 194, male connector 158 is restricted from being released from female connector 194 when an upwards tension force is applied against male connector 158.
In the configuration described above, female connector assembly 180 is configured to act as a dampener when a force is applied in either a first or upper (relative sea floor 3) direction 193 or a second or downwards (relative sea floor 3) direction 195. Specifically, when a force is applied against female connector 194 in a first or upwards (relative sea floor 3) direction 193, the fluid disposed in upper chamber 184 a of cylinder 182 is compressed, thereby absorbing shock and dissipating energy from the upwards force 193. Also, when a force is applied against female connector 194 in a second or downwards (relative sea floor 3) direction 195, sea water disposed in lower chamber 184 b is ejected from volume 184 via ports 188 at the lower end 182 b of cylinder 182. Ports 188 are tuned to optimize the flow of the ejected sea water so as to absorb shock and dissipate energy from the downwards force 195. In this manner, female connector assembly 180 is configured to reduce shocks and dissipate energy in response to forces applied to BOP assembly 100 once BOP assembly 100 couples with anchoring assemblies 160 via hawsers 124.
Referring to FIG. 5, as BOP assembly 100 is lowered towards sea floor 3, BOP assembly 100 will enter a target location disposed proximal sea floor 3. Once BOP assembly 100 is disposed in the target location, the gripper 24 of ROV 22 releases or uncoils hawsers 124 from BOP frame 102, thereby allowing male connectors 158 to descend further towards the sea floor 3. Once male connectors 158 have been released and are disposed at or near the sea floor 3, ROV 22 inserts each male connector 158 into the female connector 194 of a corresponding anchoring assembly 160 using gripper 24, thereby coupling BOP assembly 100 to anchoring assemblies 160, and in turn, the sea floor 3.
During this process, BOP assembly 100 is continuously displaced laterally, vertically, and angularly in response to transient forces 13, causing the longitudinal axis 105 to be disposed at an angular misalignment or angle 109 relative a vertical axis (i.e., extending parallel longitudinal axis 15 of wellhead 18) extending from the sea floor 3. Due to the lateral gap 107 and angular misalignment 109, the female connector assembly 180 of each anchoring assembly 160 rotates within its respective gimbal assembly 164 such that each female connector assembly 180 is axially aligned with the tension force applied by the coupled hawser 124, which is placed in tension by the moving BOP assembly 100. In this arrangement, the only substantial forces applied to female connector assemblies 180 are axial, thus limiting or eliminating the shear forces applied against female connector assemblies 180 and anchoring assemblies 160 by hawsers 124.
Further, in this arrangement female connector assemblies 180 act to damp the shock to BOP assembly 100 and anchoring assemblies 160 produced by the moving BOP assembly 100. For instance, a lull in transient forces 13 on BOP assembly 100 may allow hawsers 124 to slacken, followed by a resumption of transient forces 13 thereby causing BOP assembly 100 to be displaced away from anchoring assemblies 160 until hawsers 124 are rapidly drawn taut in response to locking devices 130 gripping hawsers 124, imparting a shock or force to both BOP assembly 100 and the anchoring assemblies 160 coupled thereto by taut hawsers 124. In this instance, the cylinders 182 and corresponding pistons 190 described above and shown in FIG. 4A damp the shock imparted to BOP assembly 100 and anchoring assemblies 160 via compressing the gas disposed in upper chamber 184 a of cylinder 182.
Referring to FIG. 6, once the male connector 158 of each retention assembly 110 is connected with the female connector 194 of a corresponding anchoring assembly 160, gripper 24 of ROV 22 is used to release the lock 118 a of each retention assembly 110, allowing each piston 118 to displace upwards towards the upper end 112 a (shown in FIG. 2) of the corresponding cylinder 112 in response to the relatively high pressure sea water acting on the lower end of each piston 118, as shown schematically in FIG. 6. Although in this embodiment releasable locks 118 a are used to release pistons 118 via gripper 24 of ROV 22, in other embodiments, pistons 118 may be released through other mechanisms, such as by transmitting a remote signal transmitted from the surface to an antenna coupled to an electronically actuated mechanism configured to release pistons 118. Further, while in this embodiment the displacement of pistons 118 through cylinders 112 tensions hawsers 124, in other embodiments, another tensioning mechanism may be used to tension hawsers 124 following the connection of male connectors 158 with female connectors 194. For instance, in an embodiment, lift bags are coupled to hawsers 124 including energetic materials for generating gas within the lift bags to provide buoyancy for tensioning hawsers 124 following the connection of male connectors 158 with female connectors 194. Alternatively, buoys may be coupled to hawsers 124 and BOP frame 102, and following the connection of male connectors 158 with female connectors 194, the buoys are released from BOP frame 102 to tension hawsers 124.
In response to the upwards displacement of pistons 118, hawsers 124 coupled to pistons 118 are also displaced upwards through cylinders 112 and locking devices 130. The displacement of hawsers 124 through cylinders 112 guides BOP assembly 100 towards anchoring assemblies 160, reducing the extent of lateral gap 107 between the longitudinal axis 105 of BOP assembly 100 and the longitudinal axis 15 of wellhead 18. In this embodiment, hawsers 124 do not necessarily pull BOP assembly 100 towards wellhead 18, and instead, guide BOP assembly 100 towards wellhead 18 while locking devices 130 restrict BOP assembly 100 from being displaced away from wellhead 18 in response to the application of transient forces 13. Particularly, locking devices 130 grip hawsers 124, restricting hawsers 124 from passing in the downwards direction 152 (shown in FIGS. 3A and 3B), in response to transient forces 13 applied against BOP assembly 100 in a direction away from anchoring assemblies 160, thereby restricting BOP assembly 100 from being displaced away from anchoring assemblies 160. However, in other embodiments, retention assemblies 110 and/or anchoring assemblies 160 include powered winches for actively pulling BOP assembly 100 towards wellhead 18 by actively retracting hawsers 124.
Referring to FIG. 7, following the release of locks 118 a of retention assemblies 110, pistons 118 continue to travel upwards through cylinders 112, thereby guiding or directing BOP assembly 100 towards well head 18 until BOP assembly 100 engages wellhead 18 and the longitudinal axis 105 of BOP assembly 100 is substantially aligned with the longitudinal axis 15 of wellhead 18. In this position, the pistons 118 of each retention assembly 110 are disposed proximal the upper end 112 a (shown in FIG. 2) of a corresponding cylinder 112. Once BOP assembly 100 has successfully landed against wellhead 18, BOP 104 is coupled or secured to wellhead 18. Following the coupling of BOP 104 to wellhead 18, the gripper 24 of ROV 22 is used to disconnect the male connector 158 of each retention assembly 110 from the female connector 194 of each corresponding anchoring assembly 160. Additional anchoring assemblies 160 mounted to BOP frame 102 (not shown) can be subsequently used to anchor and guide other components of drilling system 10 into engagement with BOP 104 in a manner similar to the guiding of BOP assembly 100 described above. For instance, in an embodiment an LMRP assembly (not shown) is guided and landed against BOP 104 in a manner similar to the guiding of BOP assembly 100 described above. In this embodiment, the LMRP assembly includes one or more retention assemblies 110 each having a male connector 158 for releasably coupling with the female connector 194 of the anchoring assemblies 160 mounted to BOP frame 102.
Referring to FIGS. 1 and 8, an embodiment of a method 200 of guiding and engaging a subsea component is shown. Starting at block 202, a subsea component is deployed below the waterline 9 in an offshore, subsea environment. In certain embodiments, prior to the subsea component being deployed below the waterline 9, anchoring assemblies are installed or coupled to the sea floor 3. In some embodiments, the process of installing anchoring assemblies at the sea floor 3 comprises coupling the frame 162 (shown in FIGS. 4A and 4B) to the sea floor 3 about wellhead 18, which is coupled to casing conductor 20 that extends through the sea floor 3. In an embodiment, block 202 comprises deploying BOP assembly 100 from drilling rig 12, where BOP assembly 100 is suspended from riser 16 that extends from drilling rig 12. At block 204, the subsea component is lowered to a target location proximal the sea floor 3. In an embodiment, block 204 comprises lowering BOP assembly 100 towards the target location proximal sea floor 3 by extending riser 16 from drilling rig 12.
At block 206, retention assemblies coupled to the subsea component are coupled to the anchoring assemblies installed at the sea floor 3. In an embodiment, block 206 comprises coupling retention assemblies 110 to anchoring assemblies 160 anchored to the sea floor 3 using the gripper 24 of ROV 22, as described above and illustrated in FIG. 5. At block 208, one or more pistons of each retention assembly is released to guide the subsea component towards the sea floor 3, and into engagement with another subsea component disposed at or near the sea floor 3. In an embodiment, block 208 comprises using the gripper 24 of ROV 22 to release the lock 118 a of each retention assembly 110, thereby releasing the piston 118 of each retention assembly 110, as described above and illustrated in FIGS. 6 and 7. In this embodiment, once BOP assembly 100 has landed against wellhead 18, BOP 104 of BOP assembly 100 is coupled to wellhead 18.
Referring to FIGS. 1, 8, and 9, block 208 of method 200 may include releasing or unlocking the locking assembly 130 of each retention assembly 110 when the lateral gap 107 between longitudinal axis 105 of BOP assembly 100 and the longitudinal axis 15 of wellhead 18 extends beyond a threshold level to allow BOP assembly 100 to become aligned with wellhead 18. Particularly, if the lateral gap 107 increases past a threshold level, the piston 118 of the retention assembly 110 in closest alignment with its corresponding anchoring assembly 160 may be displaced an unequal distance through its corresponding cylinder 114 with respect to the pistons 118 of the retention assemblies 110 further out of alignment of their corresponding anchoring assemblies 160, thereby inhibiting the alignment of the BOP assembly 100 with the wellhead 18. For instance, such a relative misalignment between retention assemblies 110 may result in an increased angular misalignment 109. In an embodiment, the lateral gap 107 may be monitored by personnel of drilling rig 12 utilizing the camera 28 of ROV 22, and in the event of an undesirable lateral offset 107, may utilize the gripper 24 of the ROV 22 to actuate the handle 146 of the locking device of the locking device 130 of the retention assembly 110 in greatest relative alignment with its corresponding anchoring assembly 160, thereby allowing the passage of hawser 124 therethrough in the upward direction 150.
Alternatively, a control system may be utilized to automatically unlock one or more of the locking devices 130 of the retention assemblies 110 in the event of a threshold level of lateral gap 107. Particularly, FIG. 9 illustrates an embodiment of a drilling system 300 including a control system for automatically releasing one or more retention assemblies 110 in response to a threshold level of lateral gap 107 between the longitudinal axis 105 of BOP assembly 100 and the longitudinal axis 15 of wellhead 18. Drilling system 300 includes features similar to those of drilling system 10, and shared features are numbered similarly. In this embodiment, the BOP assembly 100 a detector 302 in signal communication with a controller 304, where the detector is configured to actively detect or measure the extent of the lateral gap 107 between the BOP assembly 100 and the wellhead 18. In certain embodiments, detector 302 may also be configured to detect the angular misalignment 109 between the BOP assembly 100 and the wellhead 18. In this embodiment, the detector 302 comprises an optical detector; however, in other embodiments, detector 302 may comprise an acoustic, radio-frequency, or other types of detectors known in the art. In this embodiment, the detector 302 communicates with the controller 304 in real-time the extent of lateral gap 107, and in response to the lateral gap 107 exceeding a predetermined threshold level, the controller 304 is configured to adjust the tension in one or more of the hawsers 124 to optimize the placement of the BOP assembly 100 and the wellhead 18. Particularly, in this embodiment the controller 304 is configured to selectably release and/or lock one or more locking assemblies 130 in response to the lateral gap 107 exceeding a predetermined threshold level to allow the BOP assembly 100 to become re-centered with the wellhead 18. In certain embodiments, the controller 304 is further configured to displace the piston 118 of one or more retention assemblies 110 in response to the lateral gap 107 exceeding a threshold level in order to optimize placement of the BOP assembly 100 with respect to the wellhead 18.
The above discussion is meant to be illustrative of the principles and various embodiments of the present disclosure. While certain embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the disclosure. The embodiments described herein are exemplary only, and are not limiting. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.

Claims

1. A system for landing a subsea component, comprising:

a retention assembly configured to be coupled to the subsea component, the retention assembly comprising:

a first connector;

a cable extending between the connector and a tensioning assembly; and

a releasable lock configured to selectably actuate the tensioning assembly between a locked position and an unlocked position;

wherein, when the retention assembly is disposed subsea and the tensioning assembly is in the unlocked position, a tensioning force is applied to the cable in response to a hydraulic pressure force applied against the tensioning assembly by sea water from the surrounding environment; and

an anchoring assembly configured to anchor to a sea floor, the anchoring assembly comprising a second connector configured to be coupled to the first connector of the retention assembly.

2. The system of claim 1, wherein the retention assembly further comprises a locking assembly configured to allow the passage of the cable through the locking assembly in a first direction towards the retention assembly, and restrict passage of the cable through the locking assembly in a second direction away from the retention assembly.

3. The system of claim 2, wherein the tensioning assembly comprises:

a cylinder configured to couple to the subsea component; and

a piston slidably disposed in the cylinder and coupled to an end of the cable;

wherein the cylinder includes an open end for providing fluid communication between a first end of the piston and the subsea environment.

4. The system of claim 3, wherein:

when the tensioning assembly is in the locked position, the releasable lock physically engages the piston to restrict the piston from being displaced through the cylinder; and

when the tensioning assembly is in the unlocked position, the piston is displaced through the cylinder in response to fluid pressure acting against the first end of the piston.

5. The system of claim 4, wherein, in response to the piston being displaced through the cylinder, the cable is passed through the locking assembly to reduce slack in the cable.

6. The system of claim 1, wherein the anchoring assembly comprises:

a first ring concentrically disposed in a second ring, and a third ring, wherein the first and second rings are each concentrically disposed in the third ring;

wherein the first ring is pivotally coupled to the second ring such that the first ring is configured to pivot about a first axis relative to the second ring; and

wherein the second ring is pivotally coupled to the third ring such that the second ring is configured to pivot about a second axis relative to the third ring.

7. The system of claim 1, wherein the anchoring assembly comprises a damper configured to damp forces applied to the subsea component when the first connector is coupled to the second connector.

8. A system for landing a subsea component, comprising:

a first subsea component;

a retention assembly coupled to the first subsea component, the retention assembly comprising:

a first connector;

a cable extending between the connector and a tensioning assembly, wherein the tensioning assembly is configured to apply a tensioning force to the cable;

a locking assembly configured to allow the passage of the cable through the locking assembly in a first direction towards the retention assembly, and restrict passage of the cable through the locking assembly in a second direction away from the retention assembly; and

an anchoring assembly configured to anchor to a sea floor, the anchoring assembly comprising a second connector for coupling with the first connector of the retention assembly.

9. The system of claim 8, wherein the retention assembly further comprises:

wherein, when the tensioning assembly is in the unlocked position, a tensioning force is applied to the cable.

10. The system of claim 9, wherein the tensioning assembly comprises:

a cylinder coupled to the subsea component; and

a piston slidably disposed in the cylinder and coupled to an end of the cable;

wherein the cylinder has an open end for providing fluid communication between a first end of the piston and the subsea environment.

11. The system of claim 10, wherein:

12. The system of claim 11, wherein, in response to the piston being displaced through the cylinder, the cable is passed through the locking assembly to reduce slack in the cable.

13. The system of claim 8, wherein the anchoring assembly comprises:

a first ring concentrically disposed in a second ring, and a third ring, wherein the first ring and the second ring are each concentrically disposed in the third ring;

14. The system of 8, further comprising a detector configured to detect a distance between the first subsea component and a second subsea component, and a controller in signal communication with the detector, wherein the controller is configured to adjust a tensioning force applied to the cable in response to a signal transmitted to the controller from the detector.

15. A method of landing a subsea component, comprising:

deploying a subsea component in a subsea environment;

lowering the subsea component to a target location near a sea floor;

coupling a cable extending from a retention assembly coupled to the subsea component to an anchoring assembly;

actuating a tensioning assembly of the retention assembly to apply a tensioning force to the cable to guide the subsea component towards the anchoring assembly; and

passing the cable through a locking assembly to reduce slack in the cable.

16. (canceled)

17. The method of claim 15, further comprising restricting passing the cable through the locking assembly in the second direction in response to a force applied against the subsea component.

18. The method of claim 15, further comprising damping a force applied against the subsea component after coupling the cable.

19. The method of claim 15, further comprising rotating a connector of the anchoring assembly in a gimbal assembly.

20. The method of claim 15, further comprising utilizing a controller to automatically adjust a tensioning force to the cable in response to a threshold level of lateral gap between the subsea component and the target location.