Not applicable
1. Field of the Invention
This invention relates generally to systems and methods of subsea operations in the exploration and production of hydrocarbons. More specifically, the invention relates to systems and methods for forming a subsea connection over an existing subsea connection.
2. Background of the Invention
In offshore drilling operations, a blowout preventer (BOP) is installed on a wellhead at the sea floor and a lower marine riser package (LMRP) is mounted to the BOP. In addition, a drilling riser extends from a flex joint at the upper end of LMRP to a drilling vessel or rig at the sea surface. A drill string is then suspended from the rig through the drilling riser, LMRP, and the BOP into the well bore. A choke line and a kill line are also suspended from the rig and coupled to the BOP, usually as part of the drilling riser assembly.
During drilling operations, drilling fluid, or mud, is delivered through the drill string, and returned up an annulus between the drill string and casing that lines the well bore. In the event of a rapid influx of formation fluid into the annulus, commonly known as a “kick,” the BOP and/or LMRP may actuate to seal the annulus and control the well. In particular, BOPs and LMRPs comprise closure members capable of sealing and closing the well in order to prevent the release of gas or liquids from the well. Thus, the BOP and LMRP are used as devices that close, isolate, and seal the wellbore. Heavier drilling mud may be delivered through the drill string, forcing fluid from the well annulus through the choke line to balance the pressures associated with the formation fluid. Assuming the structural integrity of the well has not been compromised, drilling operations may resume. However, if drilling operations cannot be resumed, cement or heavier drilling mud is delivered into the well bore to kill the well.
In the event that the wellbore is not sealed, a blowout may occur. Such blowout may result in damage to connections between subsea well equipment. Damage to subsea connections may necessitate the need for a new connection mechanism to couple a subsea device such as a capping device to the damaged subsea connection. In cases where the subsea connection comprises mating flanges, circumstances may not allow for the separation of the existing connection. Accordingly, there is a need for systems and methods for forming subsea connections over an existing subsea connection.
These and other needs in the art are addressed in one embodiment by a subsea connection device for connecting to an existing subsea joint. In an embodiment, the device comprises a body having a central axis, a first end, a second end opposite the first end, and a throughbore extending axially from the first end to the second end. The first end comprises a connector configured to couple the body to a capping stack. In addition, the device comprises a seal element mounted in the throughbore at the second end of the body. Further, the device comprises a latching assembly disposed about the second end of the body. The latching assembly includes a base coupled to the body and a plurality of circumferentially spaced latching members pivotally coupled to the base.
These and other needs in the art are addressed in another embodiment by a method of forming a subsea connection with an existing subsea joint. In an embodiment, the method comprises (a) positioning a subsea connector adjacent an existing subsea connection. The subsea connector comprises a body having a central axis, a first end, a second end, and a throughbore extending axially between the first end and the second end. The first end comprises a connector. The subsea connector also comprises a latching assembly coupled to the body. The latching assembly comprises a plurality of circumferentially spaced latching members pivotally coupled to the body. In addition, the method comprises (b) rotating each of the latching members in a first direction to a first position. Further, the method comprises (c) receiving the existing subsea joint within the latching members. Still further, the method comprises (d) rotating each of the latching members in a second direction opposite the first direction to a second position. Moreover, the method comprises (e) engaging the existing joint with the latching members.
These and other needs in the art are addressed in another embodiment by a method for capping a subsea well. In an embodiment, the method comprises (a) coupling a subsea connector to an existing subsea joint. In addition, the method comprises (b) coupling a capping stack to the subsea connector. Further, the method comprises (c) using the capping stack to contain the subsea well.
Embodiments described herein comprise a combination of features and advantages intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical advantages of the invention in order that the detailed description of the invention that follows may be better understood. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which:
The following discussion is directed to various exemplary embodiments. However, one skilled in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.
Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.
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 . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices, components, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. Still further, as used herein, the term “ROV” refers to a remotely operate vehicle. Each ROV may include arms having a claw, a subsea camera for viewing the subsea operations (e.g., the relative positions of subsea tools or devices such subsea connection device 500), and an umbilical extending to the surface. Streaming video and/or images from cameras are communicated to the surface or other remote location via umbilical for viewing on a live or periodic basis. Arms and claws may be controlled via commands sent from the surface or other remote location to ROV through umbilical. Power may also be provided via the umbilical.
Referring now to
Downhole operations are carried out by a tubular string 116 (e.g., drillstring, production tubing string, coiled tubing, etc.) that is supported by derrick 111 and extends from platform 110 through riser 115, LMRP 140, BOP 120, and into cased wellbore 101. A downhole tool 117 is connected to the lower end of tubular string 116. In general, downhole tool 117 may comprise any suitable downhole tool(s) for drilling, completing, evaluating and/or producing wellbore 101 including, without limitation, drill bits, packers, testing equipment, perforating guns, and the like. During downhole operations, string 116, and hence tool 117 coupled thereto, may move axially, radially, and/or rotationally relative to riser 115, LMRP 140, BOP 120, and casing 131.
BOP 120 and LMRP 140 are configured to controllably seal wellbore 101 and contain hydrocarbon fluids therein. Specifically, BOP 120 has a central or longitudinal axis 125 and includes a body 123 with an upper end 123a releasably secured to LMRP 140, a lower end 123b releasably secured to wellhead 130, and a main bore 124 extending axially between upper and lower ends 123a, b. Main bore 124 is coaxially aligned with wellbore 101, thereby allowing fluid communication between wellbore 101 and main bore 124. In this embodiment, BOP 120 is releasably coupled to LMRP 140 and wellhead 130 with hydraulically actuated, mechanical wellhead-type connectors 150. In general, connectors 150 may comprise any suitable releasable wellhead-type mechanical connector such as the H-4® profile subsea connector available from VetcoGray Inc. of Houston, Tex. or the DWHC profile subsea connector available from Cameron International Corporation of Houston, Tex. Typically, such wellhead-type mechanical connectors (e.g., connectors 150) comprise a male component or coupling, labeled with reference numeral 150a herein, that is inserted into and releasably engages a mating female component or coupling, labeled with reference numeral 150b herein. In addition, BOP 120 includes a plurality of axially stacked sets of opposed rams—one set of opposed blind shear rams or blades 127 for severing tubular string 116 and sealing off wellbore 101 from riser 115 and two sets of opposed pipe rams 128, 129 for engaging string 116 and sealing the annulus around tubular string 116. In other embodiments, the BOP (e.g., 120) may also include one or more sets of opposed blind rams for sealing off wellbore when no string (e.g., string 116) or tubular extends through the main bore of the BOP (e.g., main bore 124). Each set of rams 127, 128, 129 is equipped with sealing members that engage to prohibit flow through the annulus around string 116 and/or main bore 124 when rams 127, 128, 129 is closed.
Opposed rams 127, 128, 129 are disposed in cavities that intersect main bore 124 and support rams 127, 128, 129 as they move into and out of main bore 124. Each set of rams 127, 128, 129 is actuated and transitioned between an open position and a closed position. In the open positions, rams 127, 128, 129 are radially withdrawn from main bore 124 and do not interfere with tubular string 116 or other hardware that may extend through main bore 124. However, in the closed positions, rams 127, 128, 129 are radially advanced into main bore 124 to close off and seal main bore 124 (e.g., rams 127) or the annulus around tubular string 116 (e.g., rams 128, 129). Each set of rams 127, 128, 129 is actuated and transitioned between the open and closed positions by a pair of actuators 126. In particular, each actuator 126 hydraulically moves a piston within a cylinder to move a drive rod coupled to one ram 127, 128, 129.
Referring still to
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In this embodiment, connection device 500 comprises a tubular body 501, an annular seal element 510 disposed within body 501, and a latching assembly 520 disposed about body 501. Body 501 is a rigid tubular having a central axis 505, a first or upper end 501a, a second or lower end 501b, and a throughbore 502 extending axially between ends 501a, b. Throughbore 502 allows fluids (e.g., hydrocarbon fluids) to flow through device 500. Upper end 501a comprises a connector 503 for coupling device 500 to a capping stack. In this embodiment, connector 503 is an annular flange configured to mate and engage a flange provided on the capping stack. In particular, connector 503 includes a plurality of circumferentially spaced holes 504, which are aligned with corresponding holes in the mating flange on the capping stack. With holes 504 aligned with holes in the capping stack flange, bolts are passed through each pair of aligned holes, and nuts are threaded onto the bolts and torqued down to form the flanged connection securing the capping stack to connection device 500. Although connector 503 is a connection flange in this embodiment, in general, connector 503 may comprise any suitable type of subsea connector known in the art such as a male hub configured to mate and engage with a subsea collet connector.
Referring still to
Seal element 510 has a central axis coincident with axis 505, a first or upper end 510a, a second or lower end 501b, a radially inner surface 511 extending axially between ends 510a,b, and a radially outer surface 512 extending axially between ends 510a, b. Outer surface 512 is cylindrical and sized to sealingly engage lower portion 506b of inner surface 506. Inner surface 511 is sized and shaped to mate with and sealingly engage flange connection 147. In this embodiment, inner surface 511 is contoured to mate with and sealingly engage the outer surface of lower riser portion 115a—since the outer surface of lower riser portion 115a is generally frustoconical, inner surface 511 is generally frustoconical to mate with lower riser portion 115a. In general, seal element 510 may be made of any suitable material(s) including, without limitation, a metal and metal alloy (e.g., steel, aluminum, etc.), non-metal (e.g., polymer, rubber, etc.), composite, or combinations thereof. However seal element 510 is preferably made of a metal or metal alloy suitable for the subsea environment and with sufficient strength to withstand the anticipated pressure differentials.
Referring still to
Although the rotation of latch members 526 is powered by actuators 523 in this embodiment, in other embodiments, the rotation of latch members (e.g., latch members 526) may not be powered. For example, in such embodiments, the latch members can be rotationally coupled to the base (e.g., base 521) and manually rotated about axes of rotation (e.g., axes 524) under their own weight or with a subsea ROV.
In this embodiment, each latch member 526 comprises an elongate arm 527, a clamp element or foot 528 attached to arm 527, and a fastener 529 moveably coupled to arm 527. Each arm 527 is an elongate rigid rod or shaft having a central or longitudinal axis 527c, a first or upper end 527a, and a second or lower end 527b opposite end 527a. In addition, each arm 527 extends generally vertically through a corresponding aperture 522 and is secured by the corresponding actuator 523. In this embodiment, each axis 527c, 524 are oriented such that rotation of the corresponding latch member 526 causes axis 527c to swing in a plane that contains axis 505. In other words, each axis 527c moves in a plane that is parallel to and intersects axis 505.
One clamp foot 528 is fixably attached to lower end 527b of each arm 527, and one fastener 529 is movably coupled to upper end 527a of each arm 527. Each clamp foot 528 is oriented perpendicular to its corresponding arm 527 and extends generally radially inward (relative to axis 505) from its corresponding arm 527. As will be described in more detail below, feet 528 function to engage the underside of flange joint 147 and prevent subsea connection device 500 from being pulled or moved upward and out of engagement with flex joint connection 147.
Fasteners 529 are coupled to upper ends 527a of arms 527 extending upward from base 521. In this embodiment, each fastener 529 is an internally threaded member threaded onto external threads provided on upper end 527a. To provide sufficient clearance for fasteners 529 as latch members 526 pivot relative to base 521, apertures 522 are tapered. Namely, the width or inner diameter of each aperture 522 generally decreases moving axially downward through base 521. As will be described in more detail below, fasteners 529 are employed to compress or squeeze flange joint 147 between base 521 and feet 528, thereby securing connection device 500 to flex joint connection 147. As shown in
Referring now to
Latch members 526 are sized and positioned such that (a) feet 528 are radially spaced away from and do not interfere with flange joint 147 with connection device 500 in the open position, thereby allowing connection device 500 to be mounted to flange joint 147; and (b) feet 528 are positioned to engage flange joint 147 from below, thereby allowing connection device 500 to be secured to flange joint 147. In this embodiment, axes 527c are oriented parallel to axis 505 (and perpendicular to base 521) in the closed position, and axes 527c are oriented at an acute angle β relative to axis 505 in the open position.
As shown in phantom in
As previously described, subsea connection device 500 couples an existing subsea joint (e.g., joint 147) to a capping stack. In particular, connector 503 at upper end 501a attaches device 500 to the capping stack. For example, as shown in
Referring now to
For subsea deployment and installation of connection device 500, one or more remote operated vehicles (ROVs) are preferably employed to aid in positioning device 500, monitoring device 500, BOP 120, and LMRP 140, and transitioning device 500 between the open and closed positions. Each ROV 170 includes an arm 171 having a claw 172 at its distal end, a subsea camera 173 for viewing the subsea operations (e.g., the relative positions of device 500, plume 160, the positions and movement of arms 170, etc.), and an umbilical 174. Streaming video and/or images from cameras 173 are communicated to the surface or other remote location via umbilical 174 for viewing on a live or periodic basis. Arms 171 and associated claws are controlled via commands sent from the surface or other remote location to ROV 170 through umbilical 174.
Referring to
Using cables 180, connection device 500 is lowered subsea under its own weight from a location generally above and laterally offset from wellbore 101, BOP 120, and LMRP 140. More specifically, during deployment, connection device 500 is preferably maintained outside of plume 160 of hydrocarbon fluids emitted from wellbore 101. Lowering device 500 subsea in plume 160 may trigger the undesirable formation of hydrates within device 500, particularly at elevations substantially above sea floor 103 where the temperature of hydrocarbons in plume 160 is relatively low.
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Capping stack 700 is preferably deployed subsea in the same manner as connection device 500 previously described. Namely, capping stack 700 is lowered subsea (with cables or pipestring) to connection device 500 laterally offset from BOP 120 and outside of plume 160. Once in position laterally adjacent and slightly above device 500, capping stack 700 is moved laterally over device 500, substantially coaxially aligned with device 500, and lowered on to connector 503. Next, capping stack 700 is secured to connector 503 to form a fluid tight connection with connection device 500. Capping stack 700 contains actuatable ram BOPs known in the art that are maintained open during deployment and installation, but which may be gradually closed following installation to shut in wellbore 101.
In the embodiment of the deployment and installation method shown in
Although embodiments of subsea connection device 500 have been discussed with respect to a flange joint 147 between riser 115 and flex joint 143, embodiments of connection devices described herein (e.g., connection device 500) may be used in connection with other types of existing subsea joints or in connection with flange 145a following removal of riser 118. In such an embodiment, seal element 510 is preferably sized and shaped to mate with and sealingly engage flange 145a as opposed to lower riser portion 115a. For example, instead of an angled or tapered profile, seal element 510 may have a notched, stepped or completely flat profile. Further, embodiments described herein may also be used for other purposes other than capping or producing a subsea wellbore. In an exemplary embodiment, subsea connection device 500 may be used to provide a subsea connection in cases where the upper and lower portions of a flange connection are unable to be separated. The installation of subsea connection device 500 would be similar as described above with out the complications of having to deal with the discharge of hydrocarbons.
While preferred embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the invention. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.
This application claims benefit of U.S. provisional patent application Ser. No. 61/498,933 filed Jun. 20, 2011, and entitled “Subsea Connector with a Latching Assembly,” which is hereby incorporated herein by reference in its entirety.
Number | Date | Country | |
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61498933 | Jun 2011 | US |