Method and system for deep sea drilling

Abstract

The present invention is directed to an underwater drilling system that includes a shuttle for transporting drill rods, geophysical tools, and/or core barrels from the underwater drilling platform to a surface vessel and/or a robotic vehicle to provide power to the underwater drilling platform and monitor and/or control the operation of the underwater drilling platform.

Description

FIELD

The invention relates generally to resource exploration and exploitation and particularly to resource exploration and exploitation in underwater deposits.

BACKGROUND

Vast mineral and hydrocarbon resources are located under the oceans of the world. Only a small portion of these resources is currently being exploited. Off shore exploratory drilling for and production of hydrocarbons have been performed for over thirty years. Technological advances have greatly extended the ocean depth to which hydrocarbon deposits may now be commercialized. Manganese nodules have been mined for years from the ocean floor. Notwithstanding these efforts, suboceanic deposit exploitation is only in its infancy. A major stumbling block to exploiting the deposits is finding them at a reasonable cost.

Exploratory drilling for mineral deposits, such as base and precious metal deposits, is conventionally done in surface deposits by core drilling. In core drilling, drill rods are attached to a drill bit which forms a cylindrical core of in situ material positioned within the rods as the drill bit penetrates the rock. A core barrel is movably disposed within the drill rods by a wire-line cable to capture the cylindrical core and transport it to the surface. The core may be analyzed for geological factors indicating the presence of valuable minerals.

A number of underwater drilling systems are currently available; however, none of the systems provides a wire-line core barrel recovery system. In one type of ocean drilling system, a line of drill rods extends from the ocean floor to a surface vessel. The surface vessel includes the drilling platform and a heave compensation system to continuously adjust the position of the drilling platform on the ship to compensate for the ocean swell and correctly reference the drilling forces to the drill bit on the ocean floor. The drill rod string has to support itself and transmit the drilling forces from the ship to the ocean floor while the ship continuously positions itself over the drill hole on the ocean floor. A large, high powered system is normally required to perform these functions. In another type of ocean drilling system, the drilling platform sits on the ocean floor. The drilling platform is self-contained, including power, instrumentation, and manipulative systems to allow the drill to operate as an independent ocean bottom system under the drill ship. Ocean floor drilling platforms typically lack substantial power systems, have slow drilling rates, and provide poor control of the drilling process with consequent highly variable core recoveries.

SUMMARY

These and other needs are addressed by the various embodiments and configurations of the present invention. The present invention is directed to an underwater drilling system that includes a drilling platform positioned on the bottom of a body of water.

In one embodiment of the present invention, the underwater drilling system includes:

(a) an underwater drilling platform positioned on the bottom;

(b) a surface vessel; and

(c) a submersible robotic vehicle movable between the underwater drilling platform and surface vessel. The robotic vehicle performs one or more of the following underwater operations:

• • (i) providing power to the underwater drilling platform;
  • (ii) monitoring and/or controlling the operation of the underwater drilling platform;
  • (iii) assembling drill rods to form a drill string; and
  • (iv) recovering a core barrel from the drill string and transporting the core barrel to the surface.

In another embodiment, the underwater drilling system includes:

(a) an underwater drilling platform positioned on the bottom;

(b) a surface vessel; and

(c) a shuttle movable between the surface vessel and underwater drilling platform. The shuttle carries one or more of a tool, rod, and core barrel between the surface vessel and the drilling platform.

The various embodiments of the present invention can provide a number of advantages over conventional systems. First, an underwater drilling platform can eliminate the need for a heave compensation system to manage movement of the supporting surface vessel during drilling, thereby avoiding weight and reducing capital and operating costs. The underwater drilling platform can control the drilling forces precisely. Second, the shuttle mating system can allow the core barrel and wire-line tools to transfer from the drill string into the shuttle, or vice versa, without exposure to the currents and motion of the surrounding water. Thus, the shuttle can allow core drilling to be done in deep waters without a drill string extending to the surface. This can avoid the need in the drilling system to accommodate a large amount of weight from a drill string extending to the surface. Moreover, the wire-line shuttle can allow rapid transit times for core recovery and for the wire-line tools to be transferred between the drilling platform and surface vessel. Third, the drill operator can control the drilling operations using a surface control system on the surface vessel that is linked to the drilling platform through the robotic vehicle. Fourth, the robotic vehicle can provide power to the drilling platform, which simplifies the drilling platform and reduces the cost of building a power and communications system on the drilling platform and/or surface vessel to operate the drill. Suitable robotic vehicles are currently in use in other applications. Fifth, the robotic vehicle can provide an ability to work on and around the drilling platform using the capabilities of the robotic vehicle with the various tools and manipulators that can be fitted to the vehicle. Thus, the drilling platform itself is required to have only very basic capabilities as more complex jobs can be done by the vehicle. Sixth, the use of mating systems to connect the rod string to the drilling platform and the wire-line shuttle to the rod string can allow drilling to be continued to an arbitrary depth. The mating system can also allow the core to be removed from the drill string without pulling the rods and allow the running of geophysical logs at any time.

These and other advantages will be apparent from the disclosure of the invention(s) contained herein.

The above-described embodiments and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.

As used herein, “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing the deployment of an underwater drilling system according to an embodiment of the present invention;

FIG. 2 is a side view of the underwater drilling system of FIG. 1;

FIGS. 3A and 3B are side and front views, respectively, of the underwater drilling system of FIG. 1;

FIG. 4 is a side view of a shuttle according to an embodiment of the present invention;

FIG. 5 is a cross-sectional view of the shuttle of FIG. 4; and

FIG. 6 is a side view of a carrier according to an embodiment of the present invention.

DETAILED DESCRIPTION

A first embodiment of the present invention will be discussed with reference to FIGS. 1 and 2. The underwater drilling system 100 includes a supporting surface vessel 104, such as a ship or barge, anchored or otherwise maintained in a relatively fixed position, a drilling platform 108 located on the bottom 112 (e.g., sea floor or ocean floor), a shuttle 124 for moving geophysical logging tools, rods, core barrels, and other articles between the vessel 104 and bottom 112, an anchor line 116 for moving the shuttle 124, a wire-line cable 120 for deploying geophysical logging tools (e.g, sonic, density, borehole gravity, and electromagnetic sensors) in the drilled hole and retrieving the core barrel from and deploying the core barrel in the drilled hole, and a Robotic Ocean Vehicle or ROV assembly 128 in electrical communication with the drilling platform 108. The surface vessel 104 includes a first winch 150 attached to the anchor cable 116 to raise and lower the drilling platform 108 and a second winch 154 attached to the wire-line cable to raise and lower the shuttle 124.

The drilling platform 108 includes a platform 200 gravitationally resting on or otherwise anchored to the bottom 112, a drill string 204 including one or more rotatably connected drill rods in communication with a drill bit 208, a moveable automatic chuck 212 to clamp and/or unscrew rods in the drill string, actuators 216 (such as hydraulic rams or electric actuators) to move the chuck 212 up and down, a fixed automatic chuck 220 to clamp the drill string 204 when the moveable chuck 212 is not gripping a rod in the drill string or is unscrewing a drill rod, and a mast 224 attached to the anchor cable 116. It may also include a mud and water pump system (not shown) to provide drilling fluids to the drill bit while drilling, force feedback and instrumentation to allow a full assessment of the drilling operation, an automatic leveling and anchoring system to simplify set up on an irregular bottom, a survey system including sonar transponders or equivalent underwater systems to allow accurate positioning of the drilling platform, a video system independent of the ROV assembly to allow monitoring of the drilling operation, and a maneuvering system, such as crawlers or walking legs, to permit the drilling platform to move independently of the ROV assembly. As will be appreciated, the drill string 208 includes one or more drill rods screwed together with the drill bit 208 and wire-line fitting (not shown) at the bottom end of the drill string. A motive drive (not shown) is located in the platform 200 to rotate the drill string 204 and drill bit 208 and advance the drill hole downwards. The rods in the drill string provide a transfer of drilling forces to the drill bit from the motive drive. As will be appreciated, the moveable automatic chuck and actuators apply downward force during drilling and the joint action of the fixed and moveable chucks can remove the drill string from the hole and successively unscrew rods from the drill string.

The shuttle 124 will now be described with reference to FIGS. 3A, 3B, and 4-5. The shuttle 124 includes a shuttle barrel 400 that surrounds the rod contained within it and turns freely to allow the rod to be connected and mated to the rod string, a shuttle barrel guide 404 that holds the shuttle barrel 400, a shuttle barrel end cap 408, and an actuator and automatic chuck assembly 412. The shuttle barrel is rotatably mounted in the shuttle barrel guide 404 (such as by bearings) to permit the barrel 400 to rotate freely. The shuttle barrel guide 404 includes upper and lower arms 406a,b slidably engaging the anchor cable 116 to allow the shuttle 124 to freely travel up and down the anchor cable 116. The shuttle barrel 400 projects out of the shuttle barrel guide 404 at the bottom end of the guide 404.

The shuttle barrel end cap 408 can be of two different configurations. In one configuration, the wire-line cable 120 passes through the end cap 408 to connect to a logging tool or core barrel 550. In this configuration, the logging tool or core barrel is positioned inside of a carrier (discussed below) which is itself positioned inside of the shuttle barrel. In the other configuration, the wire-line cable only connects to the end cap 408 (commonly without passing through it) for transporting an ordinary rod. The rod is located within the barrel 400. Both types support the shuttle 124 when the shuttle 124 and its contents are traveling to and from the bottom 112. In other words, the wire-line cable moves the shuttle 124 to and from the bottom 112. The actuator and automatic chuck assembly 412 includes a power supply (not shown), such as a battery, an actuator 500, a chuck 504, and communication and control equipment to allow remote operation. The actuator 500 opens and closes a closure member of the carrier to effect removal of the core barrel or wire-line logging tools. The chuck 504 grips and holds the rod in place during transit to and from the surface vessel 104.

As can be seen from FIGS. 4-5, the bottom end of the transported rod 430 (or carrier) projects out of the bottom of the shuttle barrel 400 to permit the exposed lower end of the rod to connect to the upper end 370 of the drill string 204. The automatic chuck 212 screws the rod into the drill string's upper end 370. As can be seen in FIG. 2, the mast 224 includes a guide member 250 to guide the protruding end of the rod onto the upper end 370 of the drill string. The guide member 250 can be a funnel as shown, orienting plate, or have any other type of guiding member design. During the mating of the bottom end of the transported rod 430 and upper end 370 of the drill string, the shuttle barrel turns freely. The chuck 212 grips, aligns, and screws the rod 430 (or carrier) onto the drill string. When the transported rod is to be left at the ocean bottom, the shuttle's automatic chuck 504 is operated remotely to release the rod and leave it attached to the drill string. The reverse operation is used to remove a rod from the drill string. In other words, the rod is positioned within the shuttle, gripped by the chuck 504, and unscrewed from the drill string by the chuck 212. When a geophysical tool or core barrel is being delivered or removed, the chuck 212 screws the lower end of the carrier onto the drill string, the actuator 500 opens the carrier, and the wire-line cable is used to lower the tool or core barrel in the drill hole in the normal manner. Once the tool or core barrel is returned to the carrier, the actuator 500 closes the carrier, and the chuck 212 unscrews the carrier from the rod string. The shuttle 124 is then lifted to the surface by the wire-line cable.

The carrier will now be discussed with reference to FIGS. 5-6. The carrier 508 encloses geophysical logging tools (not shown) or the core barrel 512 (which travel inside of the rods in the drilling string when deployed down hole). It includes a closure member 516, such as a stop cock or other type of valve, to seal the contents from water when the shuttle is in transit. This prevents the core in the core barrel from being degraded due to exposure to water movement. As can be seen from FIG. 5, the wire-line cable 120 passes through the end cap 408 and grips the core barrel 512. The lower end 520 of the carrier 508 is threaded to engage the upper end 370 of the drill string 204. The closure member 516 is opened and closed by the actuator 500. The closure member may be opened before or after mating of the lower end 520 with the upper end 370 of the drill string. The outer diameter of the carrier 508 is substantially similar to the outer diameter of the rod 430 so that it may be gripped by the chuck 212. The carrier remains screwed onto or engaged with the drill string while the wire-line cable and attached tool/core barrel is deployed in the drill hole. Normally, it is unscrewed from or disengaged with the drill string only when the attached geophysical tool or core barrel is properly positioned within the carrier. The closure member may be closed before or after disengagement of the carrier from the drill string. The chuck 504 grips the carrier while the carrier is lifted to the surface by the wire-line cable.

Referring again to FIGS. 1-2, the ROV assembly 128 will now be described. The ROV assembly 128 is independently controllable and provides the principal power and control systems connecting the surface vessel 104 and the drilling platform 108. Although the drilling platform 108 typically includes an auxiliary power source, the primary source of power for the drilling platform 108 is the ROV assembly 128, which connects to a power take off 270 (FIG. 2). The power take off 270 can also effect the exchange of communication signals between the computational components (e.g., instrumentation and control systems) in the drilling platform and the surface vessel. As will be appreciated, the drilling platform normally includes a suite of sensors, such as acoustic sensors, video cameras, pressure sensors, torque sensors, and Revolutions-Per-Minute or RPM sensors, to monitor its various operations. In this manner, the surface vessel is able to remotely control and supervise the operations of the drilling platform 108. The ROV assembly can work around the drill and operate the drill using its own tools and manipulator arms if required so that specialized tools are not required on the drilling platform itself to complete complex sequences of work.

The ROV assembly commonly includes a heavy armored umbilical cable 280, a transition unit 284, a garage 286 to house and constrain the movement of the transition unit 284, a lightweight tether 288, and an ROV 292. As will be appreciated, the garage and transition unit 284 rest on the bottom 112, provide the transition between the heavy armored umbilical cable 280 and lightweight tether 228, and provide a fixed point about which the ROV 292 moves. The umbilical cable 280 and lightweight tether carry power and communications, optical fibers for video and digital telemetry, and the like. The ROV assembly may be any commercially available ROV assembly modified for the present application. Examples of commercially available ROV assemblys include those manufactured by Perry Slingsby™, ISE™, and SMD Hydrovision™.

Although the present invention is discussed with reference to the ROV assembly of FIG. 2, it is to be understood that any submersible robotic underwater vehicle, whether manned or unmanned, may be employed.

A number of variations and modifications of the invention can be used. It would be possible to provide for some features of the invention without providing others.

For example in one alternative embodiment, the mating systems on the drilling platform for the drill string and wire-line shuttle are omitted. The drilling platform is preloaded with a drill string at the surface and then lowered to the bottom to drill a fixed distance, e.g., one mining bench.

In another alternative embodiment, no shuttle is required. The drilling platform, drill string, core barrel(s), and drilling supplies are lowered separately. The ROV assembly then assembles the various components at the bottom.

In yet another embodiment, the anchor cable 116 is omitted. The drilling platform is not attached to the surface vessel.

In yet another embodiment, a power cable from the ship is connected to the drilling platform and provides the primary source of power. The ROV assembly is used as an aid and supervisory system.

In yet another embodiment, the drilling platform is used to drill exploratory or production wells for hydrocarbons. In this application, no core barrel is normally employed.

The present invention, in various embodiments, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various embodiments, subcombinations, and subsets thereof. Those of skill in the art will understand how to make and use the present invention after understanding the present disclosure. The present invention, in various embodiments, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and/or reducing cost of implementation.

The foregoing discussion of the invention has been presented for purposes of illustration and description. The foregoing is not intended to limit the invention to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the invention.

Moreover, though the description of the invention has included description of one or more embodiments and certain variations and modifications, other variations and modifications are within the scope of the invention, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative embodiments to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.

Claims

1. An underwater drilling system, comprising: (a) an underwater drilling platform positioned on the bottom; (b) a surface vessel; and (c) a submersible robotic vehicle movable between the underwater drilling platform and surface vessel and operable to perform at least one of the following underwater operations: (i) provide power to the underwater drilling platform; (ii) monitor and/or control the operation of the underwater drilling platform; (iii) assemble drill rods to form a drill string; and (iv) recover a core barrel from the drill string and transport the core barrel to the surface.

2. The underwater drilling system of claim 1, wherein the robotic vehicle is operable to perform operation (i).

3. The underwater drilling system of claim 1, wherein the robotic vehicle is operable to perform operation (ii).

4. The underwater drilling system of claim 1, wherein the robotic vehicle is operable to perform operation (iii).

5. The underwater drilling system of claim 1, wherein the robotic vehicle is operable to perform operation (iv).

6. The underwater drilling system of claim 1, further comprising: (d) an anchor cable extending between the surface vessel and drilling platform; and (e) a shuttle movably engaging the anchor cable and movable between the surface vessel and drilling platform.

7. The underwater drilling system of claim 6, wherein the drilling platform comprises a fixed chuck, a moveable chuck, and an actuator engaging the moveable chuck and wherein the actuator displaces the moveable chuck along a longitudinal axis of a drill string operatively engaging the drilling platform.

8. The underwater drilling system of claim 6, wherein the shuttle comprises a shuttle barrel for receiving a rod, a shuttle barrel guide for engaging the anchor cable, a shuttle barrel end cap engaging a wire-line cable extending between the shuttle and the surface vessel, and a chuck for gripping a drill rod positioned within the shuttle barrel.

9. The underwater drilling system of claim 6, wherein the shuttle comprises a carrier for receiving a core barrel, a shuttle barrel for receiving the carrier, a shuttle barrel guide for engaging the anchor cable, and a shuttle barrel end cap engaging a wire-line cable extending between the shuttle.

10. The underwater drilling system of claim 9, wherein the wire-line cable passes through the end cap and the carrier comprises a closure member for sealing the interior of the carrier from the ambient water.

11. The underwater drilling system of claim 6, wherein the drilling platform comprises a guide member to direct the rod, which protrudes from the shuttle, to mate with an upper end of the drill string.

12. An underwater drilling system, comprising: (a) an underwater drilling platform positioned on the bottom; (b) a surface vessel; and (c) a shuttle movable between the surface vessel and underwater drilling platform, wherein the shuttle carries at least one of a tool, rod, and core barrel between the surface vessel and the drilling platform.

13. The underwater drilling system of claim 12, further comprising: (d) a submersible underwater robotic vehicle movable between the underwater drilling platform and surface vessel and operable to perform at least one of the following underwater operations: (i) provide power to the underwater drilling platform; (ii) monitor and/or control the operation of the underwater drilling platform; (iii) assemble drill rods to form a drill string; and (iv) recover a core barrel from the drill string and transport the core barrel to the surface.

14. The underwater drilling system of claim 12, further comprising: (d) an anchor cable extending between the surface vessel and drilling platform, wherein the shuttle moves along the anchor cable between the surface vessel and drilling platform.

15. The underwater drilling system of claim 14, wherein the shuttle comprises a shuttle barrel for receiving a rod, a shuttle barrel guide for engaging the anchor cable, a shuttle barrel end cap engaging a wire-line cable extending between the shuttle and the surface vessel, and a chuck for gripping a drill rod positioned within the shuttle barrel.

16. The underwater drilling system of claim 14, wherein the shuttle comprises a carrier for receiving a core barrel, a shuttle barrel for receiving the carrier, a shuttle barrel guide for engaging the anchor cable, and a shuttle barrel end cap engaging a wire-line cable extending between the shuttle.

17. The underwater drilling system of claim 16, wherein the wire-line cable passes through the end cap and the carrier comprises a closure member for sealing the interior of the carrier from the ambient water.

18. The underwater drilling system of claim 14, wherein the drilling platform comprises a guide member to direct the rod, which protrudes from the shuttle, to mate with an upper end of the drill string.

19. An underwater drilling method, comprising: (a) transporting a shuttle from a surface vessel to an underwater drilling platform, wherein the shuttle carries at least one of a drill rod, geophysical tool, and a core barrel; (b) positioning the shuttle over a drill string at the underwater drilling platform; and (c) engaging the at least one of a drill rod, geophysical tool, and core barrel with the drill string.

20. The method of claim 19, wherein the shuttle is transported between the surface vessel and underwater drilling platform along an anchor cable.

21. The method of claim 20, wherein the shuttle comprises a shuttle barrel for receiving the at least one of a drill rod, geophysical tool, and core barrel, a shuttle barrel guide for engaging the anchor cable, and a shuttle barrel end cap engaging a wire-line cable extending between the shuttle and the surface vessel.

22. The method of claim 21, wherein the shuttle comprises a chuck for gripping at least one of a drill rod and carrier positioned within the shuttle barrel.

23. The method of claim 22, wherein the at least one of a drill rod, geophysical tool, and core barrel is a geophysical tool and/or core barrel, wherein the at least one of a drill rod and carrier is a carrier, wherein the wire-line cable passes through the end cap, and wherein the carrier comprises a closure member for sealing the interior of the carrier from the ambient water.

24. The method of claim 23, wherein engaging step comprises the substeps: (c1) connecting an end of the carrier with an upper end of the drill string; and (c2) the wire-line cable lowering the geophysical tool and/or core barrel into the drill string.

25. The method of claim 24, further comprising: (d) the wire-line cable raising the geophysical tool and/or core barrel into the carrier; (e) disconnecting the end of the carrier from the upper end of the drill string; (f) closing the closure member; (g) after step (f), transporting the shuttle from the drilling platform to the surface vessel.

26. The method of claim 19, further comprising: a robotic vehicle performing at least one of the following steps: (i) providing power to the underwater drilling platform and (ii) monitoring and/or controlling the operation of the underwater drilling platform.