Patent Grant
9855999
The present embodiments relate to a launch and recovery system for a Remotely Operated Vehicle (ROV) with a pass through tether management system.
Many underwater operations, such as drilling for and production of oil and gas, installation and maintenance of offshore structures, or laying and maintaining underwater pipelines require the use of a remotely operated vehicle (ROV).
An (ROV) is a tethered underwater mobile device. ROVs are typically unoccupied, highly maneuverable, and operated by a dedicated crew aboard a vessel. The deployment of an ROV is typically achieved by launching the unit from either a bottom founded host platform, a floating host platform, or from a dynamically positioned marine vessel dedicated specifically for the purpose of supporting an ROV and/or other installation and subsea intervention equipment, e.g. a multi service vessel (MSV).
Often when working in rough seas or in deeper water, a load-carrying umbilical cable is used along with a tether management system (TMS). The TMS can be a large garage-like housing which contains the ROV during lowering. The TMS can also be a separate system which sits atop the ROV.
The purpose of the TMS is to house the tether and ROV during lowering, and lengthen and shorten the tether during operation. The TMS effectively allows power to be supplied to the ROV, as well as minimizes the effect of cable drag where there are strong underwater currents.
The umbilical cable is an armored cable that contains a group of electrical conductors and fiber optics that carry electric power, video, and data signals between the operator and the TMS. Where used, the TMS then relays the signals and power for the ROV down the tether cable.
Both bottom founded and floating host platforms can be fixed in position at the site and are normally engaged in collateral activities such as drilling and offshore production or construction. Thus, the operations of the ROV can be limited according to the distance that the ROV can travel from the host platform as well as by restrictions in operating periods due to the collateral activities of the host platform.
In the case of dedicated vessel deployment such as an MSV, significant costs can be associated with operation of a fully founded marine vessel and its mobilization to and from the ROV work site. Typically, a dedicated MSV may have a crew of twenty, large cranes with Active Heave Compensation (AHC), and other considerable costs not directly related to the operation of the ROV.
ROV operation and monitoring can be controlled from the host platform or MSV by means of an umbilical line between the host platform or MSV and the Tether Management System (TMS) which stores a limited amount of tether to connect to the ROV. It can be seen from this that the operational distance of the ROV can be directly related to the length of the tether capacity on the TMS unit.
A need exists for an improved launch and recovery system that utilizes pass through tether management system concepts and advantages while addressing most prominent drawbacks of current systems.
A further need exists for an improved launch and recovery system that can be containerization for standard shipping that can include simple accurate active heave compensation and that has passive guidance for heavy weather deployments.
A further need exists for an improved launch and recovery system that include redundant passive overload protection that eliminates the need for hydraulic power units and can have easy dead ROV recovery capability.
A further need exists for a pass through tether management system with a tether management component connected to the launch and recovery system enabling a remotely operated vehicle (ROV) to be lifted and deployed in water without the need for an armored umbilical.
The present invention meets these needs.
The detailed description will be better understood in conjunction with the accompanying drawings as follows:
Embodiments of the present invention are detailed below with reference to the listed Figures.
Before explaining the present invention in detail, it is to be understood that the invention is not limited to the particular embodiments detailed below, and that it can be practiced or carried out in various ways.
The present embodiments relate to a launch and recovery system (LARS) with a tether management system (TMS) utilizing a pass through (PT) tether for an offshore object. Herein, the embodiments can be referred to as pass through tether management system (PT-TMS).
The embodiments can turn a free flying system into a “TMS controlled” system by separately supporting the TMS frame (and/or lift frame) with an independent load line so the tether or umbilical only passes through the frame going direct to the ROV.
In embodiments, the tether or umbilical can act as the load line. In such an embodiment, a traction system can move the TMS along the length of the tether, with a separate mechanism for attachment of the ROV and a separate mechanism to lower/remove the system from the water.
A traction system in the PT-TMS coupled with a constant tension system on the LARS topside maintains the tether or umbilical directly below the LARS down to the desired working depth thereby avoiding any slack or impacts of current forces.
The traction system can be controlled e.g. by direct cable, a communication line with battery power, or battery power with wireless communications such as an acoustic modem.
The embodiments eliminate the need for armored umbilicals to support the TMS. The embodiments significantly reduce the winch size, power, and deck space. The embodiments, therefore, provide an alternative that can reduce the current total ROV systems deck weight by more than 40 percent.
The embodied system allows for the use of a smaller transport vessel and requires a smaller deck space which allows for a safer and less crowded work environment.
The present embodiments also eliminate the need for pre-tensioning and need for lebus grooved drum liners as with current armored umbilical winches. With the present embodiments, no bird caging or subsequent umbilical replacements are required.
In embodiments, a synthetic rope that is neutrally buoyant in water can be utilized so that the depth capacity of the system has no impact on LARS structure capacity. In event of damage, synthetic ropes can be field spliced.
The embodiments can provide a continuous umbilical or tether direct to the ROV, thereby eliminating the need to terminate an armored umbilical and separate delivered power to a TMS and the ROV. The continuous umbilical increases reliability and eliminates the need for an electrical and fiber optic rotary slip ring at the TMS. The present embodiments have significantly fewer connections and fewer parts and systems than current systems. Fewer connections and parts means that troubleshooting is simplified and downtime and repair costs are reduced.
The continuous umbilical in the present embodiments allows for unlimited excursion distance from the PT-TMS as the distance is limited only by total tether length less the working depth. The present embodiments also allow for ROV touchdown monitoring from a lay vessel.
The embodiments provide simpler re-terms for the tether or umbilical. The user only needs to cut back and re-connect at the ROV or connect a whole spare umbilical or tether. Traditional tether replacements are typically a full day job; that replacement time is significantly reduced with the present embodiments.
The present embodiments include a two part independent synthetic load line. The two part independent synthetic load line prevents spinning throughout deployments to depth and automatically orients the TMS and ROV for launch and recovery. These improvements eliminate the requirement for a snubber rotator. Further, these improvements allow for passive alignment fixtures to stabilize the system from swinging during launch and recoveries. Since the present embodiments do not require latching, hanging loads can be avoided thereby minimizing bending moments on A-Frame structure.
In embodiments, a capstan or traction winch can be coupled to a low tension storage reel, thereby reducing the horsepower required since the load on the traction winch is done at constant diameter; no additional power is required regardless of the depth capacity of system. Further, the speed can be constant throughout deployments at any depth.
In embodiments, a dead end of rope can first pass through a multi-sheave actuator and be used for active heave compensation with nearly zero inertial loads to overcome. Similar active heave compensation systems can be deployed for Autonomous Underwater Vehicles (AUVs)
With the present embodiments, death and injuries to workers are mitigated during heavy weather deployment and recovery activities by stabilizing the tether management component and the attached ROV through the use of the alignment receptacles and stabs of the present invention.
With the present embodiments, the chance of death and injury to workers operating the system is lessened by lowering the tension of the load lines when compared to currently available ROV launch and recovery systems.
Various embodiments can eliminate hydraulic power units (HPU) completely, therefore removing costly HPU issues, such as leaks and maintenance. The all-electric embodiments reduce the possibility of environmental disasters by eliminating the need for hydraulics entirely from the system.
The present embodiments for the systems for ROV deployment comprise at least a LARS and a PT-TMS deployment frame.
In embodiments, the LARS has at least a tether constant tension system and a crane system. The tether constant tension system can be devised to maintain back tension on tether from PT-TMS. In further embodiments, the tether can be controlled by a sliding or pivoting sheave control with weight, springs, or use of slip clutches and/or torque limiters. However, any tensioning system can be used.
In embodiments, the crane system can be used to launch and recover the PT-TMS and ROV overboard. In further embodiments, the crane can be an A-frame, a gantry, or a gantry with a telescoping end. However, any cranes can be used.
The crane system further includes one or more winches connected to the load lines for the PT-TMS and ROV. In present embodiments, traction winches, capstan winches, drum winches, and double drum winches can be used. However, any winches can be used.
The crane system further includes load lines connecting the winch or winches to the PT-TMS with ROV attached to it. In present embodiments, two or more independent load lines can be used. These load lines can be soft umbilicals (such as sonar cable) or can be rope with integral electrical or fibers. In further embodiments, a single load line can be used in a two part or basket mode. In this embodiment, the load line can be connected to a winch on one end and anchored on the opposite end or the load line can be connected to two winches or a double drum winch. The system can also utilize two single load lines in a two part mode for increased support.
Turning to the PT-TMS deployment frame, the deployment frame can be comprised of a frame, a traction system, drive motor, a power source, and means of communication and/or control.
In embodiments, the traction system can be two or more sheaves, two or more multi-pass sheaves, a cat track system, or an offset multi-roll system (similar to a pipe straightener). However, any traction systems can be used.
In embodiments, the drive motor can drive the traction system. Electrical or hydraulic drive motors can be used, but any motor may be used as well.
The power source to drive the motor can either be in the form of a direct cable, one of or more of the load lines with integral electrics, or from a battery. However, any power source can be used.
In embodiments, the communication or control can be with or without power. If without power, the communication or control can be through a direct cable or through one or more of the independent load lines. If with power, the communication or control can be through underwater wireless systems from an offshore object or the ROV. Underwater wireless communication or control can be through acoustic means or radio frequency means or optical means or other comparable systems. Herein, this type of control may be referred to as underwater wireless control means.
In embodiments, the components for the embodied systems can be built into a standard shipping container or custom frame with standard shipping container corners and dimensions. Further, the embodied systems can be mounted on top of another control cabin or container housing other accessory equipment. This reduces deck footprint and lends itself to easier installation since there is only one container to sea fasten. Vertical ISO corner clamps can be used to connect other components together.
Turning now to the Figures,
A tether management component 30 can be connected to the launch and recovery assembly 12 by the load lines 24a and 24b. The tether management component 30 can be connected to or in communication with a processor 6 and a power supply 7. Data storage 9 on the offshore object 2 can be connected to or be in communication with a power supply 7 on the offshore object. In embodiments, an acoustic transmitter receiver 19 can be connected to or in communication with the processor 6 on the offshore object 2 for communicating with the tether management component 30. The tether management component 30 can have a tether management component acoustic transmitter receiver 25 for communicating with the acoustic transmitter receiver 19 deployed from the offshore object 2, such as a ship.
The launch and recovery assembly 12 can have a base frame 14 for mounting removably to the offshore object 2. One or more pivot arms 16a can secure to the base frame 14. The pivot arms can be constructed of carbon steel, stainless steel, aluminum, or combinations thereof.
The launch and recovery system, upon instructions from the processor 6, can raise the pivot arms with actuators 17a and 17b. In embodiments, the actuators can be hydraulically or electrically driven. In further embodiments, each actuator can connect between a pivot arm and the base frame for rotating the one or more pivot arms between an onboard position and an overboard position. The plurality of actuators can be connected to or be in communication with the processor and the power supply.
The launch and recovery system 12, with instructions from the processor 6, can raise the tether management component from the deck of the offshore object 2, and then pivot the pivot arms until the tether management component is positioned overboard of the hull of the offshore object. The tether management component can then be lowered below the water surface 3.
The tether management component can latch to a remotely operated vehicle (ROV) prior to being raised; the ROV 92 and tether management component can then be deployed together into the body of water. Once in the water, the ROV 92 can de-latch from the tether management component and the ROV tether 42 can pay out through the tether management component for operation of the ROV.
In embodiments, the crane system can comprise a crane and a winch. In this Figure, the crane 28 is depicted by the pivot arms 16a and 16b and sheave 23c. However, any type of crane with associated sheave can be used.
Winches 20a and 20b can be used for deploying or recovering load lines. A first winch 20a can deploy and recover a first load line 24a. A second winch 20b can deploy and recover a second load line 24b. In basket mode, the second winch 20b can connect to the opposite end of the first load line 24a. The first and second winches can be connected to the base frame 14. Each winch can be in communication with the processor and the power supply. A plurality of sheaves 23a-23d can be mounted to the cross member. A constant tension tether assembly 26 with the remotely operated vehicle (ROV) tether 42 connected thereto is also shown.
In embodiments, the winches can be motorized.
A communication and/or power line 39 can be deployed from a take up reel 41 which can be connected to or in communication with the processor and/or the power supply.
A base frame 14, shown as rectangular in the figure, can be fastened to the offshore object. In an embodiment, the base frame can be constructed of carbon steel, stainless steel, aluminum, or combinations thereof.
The remotely operated vehicle (ROV) tether 42 for paying out over a sheave can be attached to the cross member.
A constant tension tether assembly 26 for paying in and out of an ROV tether 42 is shown. The constant tension tether assembly 26 can communicate with the processor. The constant tension tether assembly can have a movable sheave 46 for receiving the ROV tether from a sheave 23c on the cross member. The constant tension tether assembly can have an upper stationary sheave 44 for receiving the ROV tether 42 from the movable sheave 46. The constant tension tether assembly can have a storage reel 40 with a motor 47 connected to or in communication with the processor 6 for receiving instructions from the processor to take up or pay out the ROV tether from the upper stationary sheave.
As the movable sheave 46 moves up, an upper limit sensor 48 can cause a signal to the processor to activate computer instructions to instruct the processor to deploy additional ROV tether 42 from the storage reel automatically using the motor 47.
As the movable sheave 46 moves down, a lower limit sensor 49 can cause a signal to the processor to activate computer instructions to take up ROV tether 42 to the storage reel automatically using the motor 47.
The actuators can move the pivoting arm from a retracted position on the base frame to an extended position to deploy the tether management component.
In embodiments, a launch and recovery assembly 12 can have a hydraulic power unit 74 connected to actuator 17b. The hydraulic power unit 74 can communicate electronically with a processor to operate the actuator.
The movable sheave 46 can roll up and down on a rail 51 and can be mounted at substantially a 90 degree angle to the base frame 14. The movable sheave can slide in a first direction 60 along the rail 51 during deployment of the ROV tether causing payout of ROV tether from the storage reel and can slide in a second direction 61 on the rail 51 during recovering of ROV tether.
As shown in this embodiment, sheave 56a acts only to guide the tether 42, and does not control the movement of the tether. In the present embodiment, sheave 56a is designed to guide the tether without allowing the tether to reverse bend, and allows the tether to slip through the guide.
While most applications would not require, or even find it desirable to have, a pinch roller or some other traction mechanism on sheave 56a (such as a non-slip coating and the like), persons having ordinary skill in the art can determine the necessity of such traction on a case by case basis.
The tether 42 loops around sheave 56a and proceeds to sheave 56b. While sheave 56b could have the same structure as sheave 56a, sheave 56b is shown here as a series of smaller guides which may or may not roll as desired for a specific application. In the present embodiment, sheave 56b is designed to guide the tether without allowing the tether to reverse bend, and allows the tether to slip around sheave 56b.
While most applications would not require, or even find it desirable to have, a pinch roller, or some other traction mechanism on sheave 56b (such as a non-slip coating and the like), persons having ordinary skill in the art can determine the necessity of such traction on a case by case basis.
The tether 42 loops around sheave 56b and proceeds to sheave 56c. In embodiments, the ROV tether 42 can be received between sheave 56c and a pinch roller, or other similar traction mechanism. A pinch roller 59 can be mounted to the plate to contain the tether 42 against sheave 56c (See
It is important to note that sheave 56c can be used individually and independently of sheaves 56a and 56b. However, applying some manner of guide would require the tether 42 to perform a reverse bend, i.e. bend in opposite directions orthogonally to the direction of movement, which is undesirable in most applications.
In embodiments, the plate can act as a shaftless bearing housing, allowing for inserts to absorb thrust and radial loads. The plate can not only provide structural support to the tether traction device, but can contain sheets or strips of bearing materials in a cavity between components located on either side of the plate. These bearing materials can be made of polymers such as TEFLON®, or any suitable material desired by persons having ordinary skill in the art.
It is important to note that the TMS allows the tether to enter and exit the tether traction device in a substantially parallel orientation. Furthermore, it allows for minimal offset of the tether from its entry point, thereby reducing moments upon the plate used in the tether management system
In embodiments, the pass through tether management system can use an electrical cable acting as a load line for communicating from the processor and the power supply to the tether management component.
In one embodiment for the launch and recovery management systems, the systems can have cantilever telescoping arms. This embodiment can be mounted on top of control cabin or container housing with other accessory equipment to save deck space. This embodiment provides the advantage of the arms remaining above the load and provides single plane actuation. In this embodiment, the ROV can be launched or recovered sideways to save deck space and limit amount of reach required. In this orientation, electrically driven telescoping screw jacks can be used to avoid hydraulics.
This embodiment can include heave compensation with a multi-part actuator. These embodiments use a closed hydraulic system driven by a screw jack or other linear actuator to accurately drive the multi-sheave actuator. These heave compensation embodiments do not require a position sensor and do not require excessive power for inertia load when reversing the winch like with armored umbilical system. Further, the heave compensation embodiments minimize the speed and amplitude of the heave since the load is always over edge of the vessel keeping the length from the center of gravity of vessel minimal and predictable.
This embodiment can include passive guidance for heavy weather deployments. The passive guidance includes sliding stabs in the telescoping arms that intersect the PT-TMS. This aspect eliminates side loading on the LARS arms thus minimizing structural size, minimizing the swinging of the system in a freeboard area, and providing for easy adaptation to various moon pool installations.
This embodiment can include separate cage control around or on top of the PT-TMS which intersects rails on the side of the vessel. When separated from the PT-TMS, the separate cage becomes the rope guide. The cage extends to intersect and guide the ropes at deck level after lowering the ROV, thereby eliminating side loading and minimizing swinging.
With AHC, after deploying the ROV overboard, loads can be transferred to the PT-TMS. The landing of these loads can be accomplished by simply operating winch on opposite end of rope while in AHC mode. Further, the MRU can be put directly on PT-TMS to eliminate any response time or harmonic issues.
The embodiments can include overload protection by placing a dry accumulator in the closed hydraulic system of AHC actuator. The overload protection can protect from surges up to 20 feet. The dry accumulator can be set to 125 percent of max load.
As previously discussed, the AHC system can readily be modified to allow for AUVs to be launched at desired depths.
The embodiments can include run-off protection by having slip clutches integrated in LARS winch or capstan and take up reel. Using this run-off protection will prevent overloading until run out of rope. In the run-off protection, the system can be set to 150 percent max load. Further, the tether storage reel can be designed for 50 percent to 75 percent of max load.
In event of dead ROV, the ROV can be simply pulled with the LARS tether reel back through PT-TMS until bullet passively latches in frame.
The embodiments can utilize electrically driven screw jacks for AHC and telescoping LARS Arms as well as electric or air motors to drive reels and winches. The total horsepower needed to operate the system is minimized. Hydraulics are not needed, therefore, leaks and spills are eliminated and as well as the need for draining and re-filling hydraulic fluid for mobilizations. Maintenance is significantly reduced since filter changes are not required, heat exchangers are not required. Further, reliability is increased since the embodiments require fewer systems parts that could fail.
Restated, the embodiments as claimed relate to a pass through tether management system comprising a launch and recovery assembly and a tether management component. The launch and recovery assembly comprises a base frame; a crane and a winch secured to the base frame; a load line engaging the winch and passing into and through and out of a tether management component; an independent power and control line connected to the tether management component and a reel secured to the base frame; and a ROV tether secured to a constant tension tether assembly secured to the base frame. The tether management component comprises a deployment frame; a tether traction device secured to the deployment frame, wherein the tether traction device receive the ROV tether and applies tension to the ROV tether using gears and traction sheaves; and a motor connected to the tether traction device for powering the gears and traction sheaves to pay in and out the ROV tether.
Restated, the embodiments as claimed also relate to a pass through tether management system comprising a launch and recovery assembly and a tether management component. The launch and recovery assembly comprises a base frame; a crane and a winch secured to the base frame; a load line engaging the winch and passing into and through and out of a tether management component; and a ROV tether secured to a constant tension tether assembly secured to the base frame. The tether management component comprises a deployment frame; a power source and underwater wireless control means in the deployment frame; a tether traction device secured to the deployment frame, wherein the tether traction device receive the ROV tether and applies tension to the ROV tether using gears and traction sheaves; and a motor connected to the tether traction device for powering the gears and traction sheaves to pay in and out the ROV tether, wherein the motor is powered by the power source.
Restated, the embodiments as claimed also relate to a pass through tether management system comprising a launch and recovery assembly and a tether management component. The launch and recovery assembly comprises a base frame; a crane and a double drum winch secured to the base frame; a first independent load line engaging the double drum winch and connected to a tether management component; a second independent load line engaging the double drum winch connected to the tether management component, wherein the second independent load line supplies power and control to the tether management component; and a ROV tether secured to a constant tension tether assembly secured to the base frame. The tether management component comprises a deployment frame; a tether traction device secured to the deployment frame, wherein the tether traction device receive the ROV tether and applies tension to the ROV tether using gears and traction sheaves; and a motor connected to the tether traction device for powering the gears and traction sheaves to pay in and out the ROV tether.
In each claimed embodiment, the launch and recovery assembly deploys the tether management component overboard with an ROV connected and supports the tether management component with the load line, wherein the ROV is disengaged from the deployment frame for tethered operation while maintaining the tether management component at an operational depth.
While the invention has been described with emphasis on the embodiments, it should be understood that within the scope of the appended claims, the invention might be practiced other than as specifically described herein.
The current application claims priority to and the benefit of co-pending U.S. patent application Ser. No. 14/593,045 filed entitled “SYSTEM FOR LAUNCH AND RECOVERY OF REMOTE OPERATED VEHICLES”, which in turn claims priority to U.S. Provisional Patent Application Ser. No. 61/926,173 filed Jan. 10, 2014, entitled “SYSTEM FOR REMOTE OPERATED VEHICLE”. These references are hereby incorporated in their entirety.
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| Number | Date | Country | |
|---|---|---|---|
| 61926173 | Jan 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14593045 | Jan 2015 | US |
| Child | 15402152 | US |
