TOGETHER AS A SYSTEM FOR SUBSEA OIL AND GAS EXPLORATION

Inventors: Steffan Kruse Linds0

BACKGROUND

[0001] Reservoirs under the continental shelf often have seeps where gas breaks through the subsurface, creating bubbles or formations on the sea floor. Often, there is a desire to locate these seeps. In addition, it is often desirable to survey subsea environments to locate subsea opportunities, e.g. a seep, a potential mining site, hydrate, a subsea wreck, or the like, or a combination thereof.

[0002] Some work has been done on trying to locate reservoirs by locating seeps associated with them. However, the costs in such a search have always been quite large. An autonomous underwater vehicle (AUV) may be used to scan the seafloor for potential targets, and then these potential sites are followed up by a survey vessel and a remotely operated vehicle (ROV) deployed to seafloor to inspect the site. The day rate costs for vessel time are prohibitive and it has not been feasible to search for seeps in this manner. DRAWINGS

[0003] The figures supplied herein illustrate various embodiments of the invention.

Items not expressly illustrated in the drawings are not necessary for the understanding of the subject matter sought to be patented by one of ordinary skill in these arts. [0004] Fig. 1 is a schematic view of an exemplary system;

[0005] Fig. 2 is a schematic view of an exemplary AUV; and

[0006] Fig. 3 is a schematic view of an exemplary ROV. DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0007] Referring now to Fig. 1, system 1, which is useful for using a combination of multiple autonomous vehicles with different abilities working together as a system for subsea oil and gas exploration, comprises autonomous surface vessel (ASV) 10, which may be launched from a shore location and/or from a vessel; autonomously operated vehicle (AUV) 20; and remotely operated vehicle (ROV) 30. In a subsea application, system 1 operates to survey or otherwise view a subsea formation such as subsea seep location 110, formation location 120, object location 130, or the like, or a combination thereof.

[0008] ASV 10 typically comprises data transceiver 11 and power source 12 operatively in communication with data transceiver 11. Data transceiver 11 is typically configured to operate as communications link to the subsea assets, e.g. AUV 20 and ROV 30, and relays data from control station 200 to the subsea assets.

[0009] In certain embodiments, ASV 10 further comprises berth 17 for AUV 20 into which AUV 20 may be selectively released or captured.

[0010] Additionally, ASV power source 12 may comprise a battery which may be rechargeable; a fuel based electric generator; a fuel cell; or the like, or a combination thereof. In certain embodiments, where the battery is rechargeable, ASV 10 may further comprise one or more solar cells 14 operatively in communication with the rechargeable battery and operative to recharge the rechargeable battery. Further, ASV 10 may further comprise power interface 15 which is typically configured to allow refueling or recharging of power source 12 from a shore location or from a vessel.

[0011] In certain embodiments, ASV 10 further comprises tether 16 which, in these configurations, allows ROV 30 to be tethered to tether 16. [0012] Referring additionally to Fig. 2, AUV 20 typically comprises subsea survey system 21, transceiver 24 operatively in communication with subsea survey system 21, and power system 22 operatively in communication with subsea survey system 21 and with transceiver 24. AUV power source 22 may comprise battery 25, which may be rechargeable; a fuel based electric generator; a fuel cell; or the like, or a combination thereof. In embodiments, where battery 25 is rechargeable, AUV 20 may further comprise one or more solar cells 26 operatively in communication with rechargeable battery 25 and operative to recharge rechargeable battery 25.

[0013] Subsea survey system 21 may be a swappable subsea survey system, i.e. one configured to be removed and/or replaced by ASV 10 or ROV 30, and comprise a subsea formation survey package, a subsea mining opportunity survey package, a hydrate harvesting location survey package, or a treasure hunting/shipwreck site survey package, or the like, or a combination thereof. Subsea survey system 21 and its associated electronics may be used in a survey system to detect subsea seeps or other formations and/or objects.

[0014] Additionally, AUV 20 may further comprise power interface 23 configured to allow refueling or recharging of AUV power source 22 such as from a vessel or from ASV 10.

[0015] Telemetry transceiver 24 is typically in communication with AUV power source

22 and subsea survey system 21 and used to provide telemetry data to control station 200, either directly or via ASV 10, e.g. via data transceiver 11.

[0016] Referring additionally to Fig. 3, ROV 30 may be a flying eyeball ROV or a work class ROV and may be an autonomous ROV, a teleoperated ROV, or a hybrid mix of the two technologies capable of switching from autonomous operations to pre-programmed operation to teleoperation. ROV 30 typically comprises ROV power source 32 and ROV instrumentation package 31.

[0017] In embodiments ROV instrumentation package 31 typically further comprises a limitation inertial guidance system, a current profiler, sonar, a visual camera system, a light, or a sampling system for water, sediment, and the like, or a combination thereof.

[0018] ROV power source 32 may comprise a battery, a fuel based electric generator, a fuel cell, or the like, or a combination thereof.

[0019] Where ASV 10 comprises tether 16, ROV 30 typically further comprises tether power connector 36 adapted to receive power from tether 16 and power management system 37 configured to allow ROV 30 to switch from tether power to battery power and to manage power consumption to allow for low power operation and for trickle charging from lower power recharging stations.

[0020] Referring back to Fig. 1, in addition, ROV 30 is typically adapted to return to

ASV 10, return in a tethered connection to AUV 20, return to another vessel to recharge, or the like, or a combination thereof. In certain embodiments, ROV 30 is adapted to return to a nearby resident ROV (not shown in the figures) such as to recharge, upload data, and download programming/data.

[0021] In the operation of exemplary embodiments, referring back to Fig. 1, subsea surveys using system 1, which is as described above, may comprise ASV 20 which may be configured to serve as a communications link to subsea assets and relay data from control station 200 to the subsea assets, e.g. AU 20 and/or ROV 30. ASV 10 typically houses an autonomous or teleoperated ROV 30 and is further typically configured to transport an asset, e.g. ROV 30, to the sites for inspection. In addition, ASV 10 may be configured to serve as a communications link to subsea assets, e.g. AUV 20 and/or ROV 30, and to relay data from control station 200 to the subsea assets. As described above, ASV 20 may house an asset such as an autonomous or teleoperated ROV 30 and also be configured to transport that asset to sites for inspection

[0022] Surveys typically comprise deploying AUV 20 and ASV 10 to search area 100 and using AUV 20 to perform a search pattern looking for a subsea opportunity, e.g. a seep, mining site, hydrate, wreck, or the like, or a combination thereof. Telemetry may be communicated from AUV 20 back to control station 200, which may be located anywhere worldwide, either directly or via ASV 10. If something of interest is located, ASV 20 is sent to investigate potential subsea finds found by the search, e.g. a subsea opportunity (object or site or the like) of interest, such as by piloting ASV 10 to a location on or near the sea surface near the subsea find. Once ASV 10 is in that location, ROV 30 may be deployed, such as from ASV 10, and ROV 30 piloted to descend to investigate the subsea find. As noted above, ROV 30 may be operated autonomously, by pre-programmed operation, or by teleoperation and is either tethered or free swimming. ROV 30 is then used to locate and survey the subsea find and data supplied by ROV 30 relayed to control station 200, e.g. via ASV 10.

[0023] ROV 30 may be recovered to ASV 10 at a predetermined time, e.g. after ROV 30 descends and investigates the subsea find.

[0024] In embodiments, ASV 10 may be navigated to a series of subsea finds, such as after ROV 30 descends and investigates a first subsea find.

[0025] The foregoing disclosure and description of the inventions are illustrative and explanatory. Various changes in the size, shape, and materials, as well as in the details of the illustrative construction and/or an illustrative method may be made without departing from the spirit of the invention.