Patent Application
20220252185
Subsea cables are used in the oil and gas industry and the renewable energy industry to connect a host to a subsea production facility. Cables may include umbilicals that are multi-part cables. The Subsea cables may be a bundle of cables and conduits that transfer hydraulic and/or electric power within the field (long distances), or from topsides to subsea. Additionally, subsea cables may also carry fluids. The host may be a floating production storage and offloading vessel (FPSO), a floating rig, or any offshore-based facility. The host is manned, and the subsea production facility is unmanned. The subsea umbilical may include a) tubing for various fluids including hydraulic fluid, chemicals such as methanol, and/or injection/production fluids; b) electrical power cables; c) fiber optic cables; d) wire rope; e) fillers; f) reinforcements and/or combinations thereof.
Some of the subsea oil production facilities are in thousands of feet of water and therefore the conventional subsea cables may be several thousand feet long. When using umbilicals, the umbilical hangs off an I-tube or a J-tube on the host and connects to the topside umbilical termination assembly (TUTA). Subsea, the umbilical often connects to an umbilical termination assembly, referred to in the industry as a UTA. As the subsea cables are conveyed in deep waters, higher installation tensions may cause a need to have increased cable strengths to handle loads.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In one aspect, embodiments disclosed herein relate to a subsea cable transportation unit. The subsea cable transportation unit may include a base platform; a drive unit may be provided within the base platform; a storage structure may be provided on the base platform and operationally coupled to the drive unit, wherein the storage structure may be configured to receive a drum; at least one drive connection may be provided on a surface of the base platform, wherein the at least one drive connection may be operationally coupled to the drive unit and configured to provide torque or hydraulics to operate the drive unit, wherein the storage structure may be configured to rotate based on the torque or hydraulics and unspool or spool a cable wrapped around the drum; and a stabilizing fin may extend outwardly from the base platform, the stabilizing fin may include a hydrofoil. The drive unit may include a shaft having a first end attached to the at least one drive connection; a motor attached to a second end of the shaft; and a gear operationally coupled to the motor. A peripheral edge of the storage structure may include teeth and the teeth may be engaged with corresponding teeth of the gear. A level winder may be movably coupled to a rod on the base platform, wherein the level winder may be configured to move up and down the rod based on a height of the cable wrapped around the drum. A center post may extend outwardly from the base platform, the center post may include a lift connection.
In another aspect, embodiments disclosed herein relate to a subsea cable installation and recovery system. The subsea cable installation and recovery system may include a subsea cable transportation unit. The subsea cable transportation unit may include a base platform, wherein a drive unit may be provided within the base platform; a storage structure may be provided on the base platform and operationally coupled to the drive unit; a stabilizing fin may extend outwardly from the base platform, wherein the stabilizing fin may include a hydrofoil configured to displace fluids and stabilize the subsea cable transportation unit submerged in the body of water. A cable reel may be installed on the storage structure, wherein the drive unit may be configured to rotate the storage structure to turn the cable reel, wherein the cable reel may include a spool of cable wrapped around a drum. The subsea cable installation and recovery system may further include an offshore vessel at a surface of a body of water, the offshore vessel may include a crane and a line coupled to the crane, the line may be removably attached to the subsea umbilical transportation unit. The storage structure may include a locking device to lock the drum on the storage structure. A remotely-operated-vehicle (ROV) may be operationally coupled to the subsea cable transportation unit. The ROV may be removably coupled to at least one drive connection of the subsea cable transportation unit and may be configured to transmit torque or hydraulics to the drive unit through the at least one drive connection. The ROV may include thrusters to move the subsea cable transportation unit within the body of water. A level winder may be movably coupled to a rod or hydraulic cylinder on the base platform, wherein the level winder may be configured to move up and down the rod or up and down based in response to the hydraulic cylinder based on a height of the spool of cable wrapped around the drum. Further, the ROV may be operationally coupled to a hot stab of the level winder to move the level winder up and down as the height of the spool of cable changes from unspooling or spooling.
In yet another aspect, embodiments disclosed herein relate to a method. The method may include deploying a subsea cable transportation unit in a body of water at an offshore site; directing the subsea cable transportation unit through the body of water; and torqueing a drive unit provided within a base platform of the subsea cable transportation unit to drive a storage structure installed on the base platform; rotating the rotatable table with power from the drive unit, thereby unspooling or spooling a spool of cable installed on the storage structure; and stabilizing the subsea cable transportation unit in the body of water with a stabilizing fin positioned outwardly from the base platform. The deploying of the subsea cable transportation unit may include: lifting the subsea cable transportation unit off an offshore vessel with a crane attached to a post extending outwardly from the base platform; lowering the subsea cable transportation unit into the body of water with the crane; and submersing the subsea cable transportation unit in the body of water and moving the subsea cable transportation unit to a subsea site. The method may further include maintaining the subsea cable transportation unit at a distance of 20 to 50 feet above a sea floor and lowering the subsea cable transportation unit to the sea floor. The torqueing the drive unit may include operationally coupling a remotely-operated-vehicle (ROV) to a torque connection of the subsea cable transportation unit and providing a drive torque to the drive unit. The method may further include operationally coupling the ROV to a hot stab of a level winder movably coupled to the base platform, and mechanically or hydraulically moving the level winder up and down based on a height of the spool of cable, and sliding the spool of cable down a chute or ramp of the level winder.
Other aspects and advantages will be apparent from the following description and the appended claims.
Embodiments of the present disclosure will now be described in detail with reference to the accompanying Figures. Like elements in the various figures may be denoted by like reference numerals for consistency. Further, in the following detailed description of embodiments of the present disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the claimed subject matter. However, it will be apparent to one of ordinary skill in the art that the embodiments disclosed herein may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description. Additionally, it will be apparent to one of ordinary skill in the art that the scale of the elements presented in the accompanying Figures may vary without departing from the scope of the present disclosure.
As used herein, the term “coupled” or “coupled to” or “connected” or “connected to” “attached” or “attached to” may indicate establishing either a direct or indirect connection, and is not limited to either unless expressly referenced as such. Wherever possible, like or identical reference numerals are used in the figures to identify common or the same elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale for purposes of clarification. In addition, any terms designating a subsea cable installation and recovery system at an offshore vessel (i.e., any offshore rig or platform, wind or wave farms) should not be deemed to limit the scope of the disclosure. It is to be further understood that the various embodiments described herein may be used in various stages of a well or an offshore wind or an offshore wave farm, such as site preparation, drilling, completion, abandonment etc., and in other environments, such as work-over rigs, fracking installation, well-testing installation, oil and gas production installation, without departing from the scope of the present disclosure. It is recognized by the different embodiments described herein that a subsea umbilical transportation unit may play a valuable and useful role in the life of a well. Further, it is recognized that the subsea cable installation and recovery system configuration and arrangement of components for holding, storing, transporting, spooling and/or unspooling rigid and flexible pipe products, including various types of cables in a subsea environment according to one or more embodiments described herein may provide a cost effective alternative to conventional systems and eliminate tension in the cables. The embodiments are described merely as examples of useful applications, which are not limited to any specific details of the embodiments herein.
Embodiments disclosed herein relate generally to offshore industries, including, for example, subsea oil and gas operations equipment, offshore wind and wave farm equipment, or any other offshore equipment uses in any industry. More specifically, embodiments disclosed herein relate to systems and methods of use for a subsea cable installation and recovery system to provide cables to various subsea tools. In one aspect, embodiments disclosed herein relate to the subsea cable installation and recovery system including a subsea cable transportation unit having a base platform with a drive unit used for rotating a storage structure on the base platform. The subsea cable transportation unit may be used to unspool or spool cable(s) installed on the storage structure. In a non-limiting example, a stabilizing fin may extend from the base platform to displace fluids and stabilize the subsea cable transportation unit as the subsea cable transportation unit is submerged in a body of water. While the terms forward and rear are used herein, one of ordinary skill in the art will appreciate that in some embodiments a subsea cable transportation unit may move in other or opposite directions and therefore those elements labeled forward may be rear and those labeled rear may be forward.
According to embodiments of the present disclosure, cables may be rigid and/or flexible pipe products that are manufactured and/or assembled in long segments onshore for use in offshore applications. In a non-limiting example, these cables may be umbilicals, a hardline, cable, multiplexed (MUX) cable, or fluid conduits that can transmit power, fluids, or communications or any combination thereof between devices. For example, the form of communication may include, but not limited to, pressure pulses (air or liquid), electrical signals for communication over power lines, copper wires, fiber optics, or any combination thereof. In some embodiments, these cables are wound around a drum to form a spool of cable(s) for storage and transportation to an offshore vessel. In subsea environments, cables, such as fiber optic or sensor cables, may not be able to support a weight of a water column. Additionally, the cables may have a limited allowable tension from pulling forces. Embodiments of the present disclosure provide a system that may allow for reduction or elimination of tension in the cables at various depths in subsea environments. Once the subsea cable transportation unit is positioned in the subsea environments in accordance with embodiments disclosed herein, the spool of cable(s) may be unspooled or spooled without putting tension on the cables. In some embodiments, the subsea cable transportation unit may be used to unload and install a cable reel on a sea floor. The cable reel may be a bundle of the cables around a drum.
In one or more embodiments, one or more stabilizing fins 106a, 106b may extend outwardly from the base platform 101. In a non-limiting example, a first stabilizing fin 106a may be spaced a distance apart from a second stabilizing fin 106b. Additionally, both the first stabilizing fin 106a and the second stabilizing fin 106b may be positioned at the front end of the of the subsea cable transportation unit 100. In a non-limiting example, the first stabilizing fin 106a may be placed at a first corner 102a at the front end of the base platform 101. Additionally, the second stabilizing fin 106b may be placed at a second corner 102b at the front end of the base platform 101. It is further envisioned that the two stabilizing fins 106a, 106b may be placed in corners at the rear end of the base platform 101. While it is noted that only two stabilizing fins (106a, 106b) are shown, this is for example purposes only and any number of stabilizing fins may be used without departing from the present scope of the disclosure. For example, in some embodiments, two, three, or more stabilizing fins may be located on the base platform 101 and spaced apart around the perimeter of the base platform 101. Each stabilizing fin 106a, 106b may extend vertically upward from the base platform 101 and may include a shape, as discussed further below, that helps provide stability to the subsea cable transportation unit 100 as it is lowered, moved, or suspended in water. It is further envisioned that one or more support rods 111 may extend between stabilizing fins 106a, 106b, for example, from the first stabilizing fin 106a to the second stabilizing fin 106b. The one or more support rods 111 may be attached to ends of the first stabilizing fin 106a and the second stabilizing fin 106b distal from the base platform 101. The one or more support rods 111 may aid in reducing movement of the first stabilizing fin 106a and the second stabilizing fin 106b caused by the body of water. In addition, one or more brackets 143 may be provided at the ends of the first stabilizing fin 106a and/or the second stabilizing fin 106b distal from the base platform 101. The one or more brackets 143 may provide additional structural integrity to the first stabilizing fin 106a and/or the second stabilizing fin 106b from induced stresses from the body of water and operating the subsea cable transportation unit 100.
One or more stabilizing fins 106a, 106b may be a hydrofoil to displace fluids and stabilize the subsea cable transportation unit 100 submerged in the body of water. As a hydrofoil, the stabilizing fins 106a, 106b may minimize water drag on the subsea cable transportation unit 100. Additionally, the stabilizing fins 106a, 106b may aid in stabilizing, such as leveling the subsea cable transportation unit 100 or keeping the subsea cable transportation unit 100 in a straight line while moving through the body of water. In a non-limiting example, each stabilizing fin 106a, 106b may be a blade having a first surface 107 and a second surface 108. The blade may be attached to a pole 109 extending from a top surface 110 of the base platform 101. The second surface 108 may be flat and extend to the top surface 110 or the bottom surface 105 of the base platform 101. Further, the first surface 107 may have a transversely curved profile. As shown, the stabilizing fins 106a,106b are positioned such that the first surface 107 having a transversely curved profile faces away from an interior of the base platform 101. In other words, the first surface 107 having a transversely curved profile faces exteriorly. In a non-limiting example, a radius of the curved profile may gradually increase from a minimum at forward most edge 112 (in a direction of travel) to a maximum at a rearward most edge of the curved provide proximate the pole 109. The forward most edge 112 may be a position at which the first surface 107 and the second surface 108 meet distal to the pole 109. As shown in
Still referring to
As shown in
In one or more embodiments, the subsea cable transportation unit 100 may be used to unload and dispose the cable reel 113 on a sea floor. In a non-limiting example, the base platform 101 may include hydraulics to lift the cable reel 113 off the subsea cable transportation unit 100 and dispose the cable reel 113 on the sea floor. Additionally, a crane of an offshore vessel may be used to lift the cable reel 113 off the subsea cable transportation unit 100 and dispose the cable reel 113 on the sea floor. Further, an ROV may assist the subsea cable transportation unit 100 and the crane to lift the cable reel 113 off the subsea cable transportation unit 100 and dispose the cable reel 113 on the sea floor.
Referring now to
In one or more embodiments, each of the stabilizing fin 106a,106b may have one or more holes 144 at the ends of the first stabilizing fin 106a and the second stabilizing fin 106b distal from the base platform 101. The one or more holes 144 may extend downwardly into each of the stabilizing fin 106a,106b to make the each of the stabilizing fin 106a,106b partially hollow. The one or more holes 144 may allow for water to pass through so as not to trap any air within each of the stabilizing fin 106a,106b. Additionally, the storage structure 118 may include one or more through-holes 145. The one or more through-holes 145 may allow for water to flow between the storage structure 118 and the drum (115 in
In some embodiments, a drive unit 127 of the subsea cable transportation unit 100 may be installed in a housing 125 formed behind a front plate 128 of the base platform 101. The housing 125 may be interchangeably referred to as a torque bucket or hydraulic bucket. The drive unit 127 may be torque or hydraulically driven. Additionally, the front plate 128 may include an opening at which a drive connection 129 of the drive unit 127 is provided within. The drive connection 129 may be a torque or hydraulic connection. In a non-limiting example, a torque or hydraulic tool (not shown) may plug into the drive connection 129 to provide torque or hydraulic power to the drive unit 127. In a non-limiting example, the torque or hydraulic tool, such as a flying lead orientation tool (“FLOT”), may be provided by a remotely-operated-vehicle (ROV) operationally coupled to the subsea cable transportation unit 100. As shown in
In the case that the drive unit 127 is hydraulically driven, the hydraulic tool plugs into the drive connection 129 to provide hydraulics. As shown by
Still referring to
Now referring to
In some embodiments, a step 124 may be positioned on one or more corners of the base platform 101 such that the steps 124 extend past the width W of the base platform 101. The step 124 may be provided at both the first corner 102a and the second corner 102b at the front end of the base platform 101. By extending past the width W of the base platform 101, the level winder 122 may be adjacent to either stabilizing fins 106a, 106b. Additionally, the first stabilizing fin 106a and the second stabilizing fin 106b may be spaced a distance D apart from each other. In a non-limiting example, the distance D may have a value equal to or greater than the outer diameter OD of the storage structure 118. Further, a distance D′ from an outer most point of the first surface 107 of the first stabilizing fins 106a to an outer most point of the first surface 107 of the second stabilizing fins 106b is equal to the width W of the base platform 101.
In one or more embodiments, in order to deploy the subsea umbilical transportation unit 100 into the body of water 402 at a subsea well site 409, a crane 407 on the offshore vessel 401 may be used to lift the subsea cable transportation unit 100 via the center post (119 in
As shown in the dashed circle C of
In one or more embodiments, with the ROV 410 attached to the subsea cable transportation unit 100, the ROV 410 may be used to direct the subsea cable transportation unit 100 through the body of water 402. In a non-limiting example, thrusters of the ROV 410 may be used to move and provide rotational stabilization for the subsea cable transportation unit 100. Additionally, the stabilizing fins (106a, 106b in
As shown in the dashed circle D of
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting.
