US20090178848A1

US20090178848A1 - Subsea Drilling System and Method for Operating the Drilling System

Info

Publication number: US20090178848A1
Application number: US11/972,080
Authority: US
Inventors: Peter Nellessen, Jr.; Jonathan Bruce Machin; Harold Marshall Pardey
Original assignee: Perry Slingsby Systems Inc
Current assignee: TGH US Inc
Priority date: 2008-01-10
Filing date: 2008-01-10
Publication date: 2009-07-16
Also published as: AU2009203997A1; JP2011510188A; GB2469417A; GB201013403D0; WO2009089528A2; CN101970787A; NO20101128L; WO2009089528A3; BRPI0906832A2

Abstract

A subsea drilling system includes a drilling module having a tool carousel being removable and replaceable in or out of water, a skid module and an ROV to be connected to and disconnected from the skid module in or out of water, for operating the subsea drilling system with the ROV. A method for operating a subsea drilling system includes removing a tool carousel from a drilling module and replacing the tool carousel with another tool carousel, in or out of water. An ROV is connected to a skid module and disconnected from the skid module in or out of water. The subsea drilling system is operated with the ROV.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention:
The invention relates to a subsea drilling system, and more particularly to such a system having an ROV (Remote Operated Vehicle). The invention also relates to a method for operating a subsea drilling system.
2. Description of Related Art: p One existing device, built for the Monterey Research Institute, has a horizontal drill installed and operated on two ROVs. Another device, again built for the Monterey Bay Research Institute, uses a skid. However, in that device, a carousel is fixed and mounted horizontally. The subsea drilling system has a removable carousel that is mounted vertically.

BRIEF SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a subsea drilling system and a method for operating the subsea drilling system, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type, in which a carousel is removable on the surface or subsea, is guided into place by pins and guide receptacles and can be removed or replaced under water using another ROV, in which the system is capable of mating under water with an ROV, so that the ROV can connect to and operate the subsea drilling system and in which the ROV can also disconnect from a subsea drilling system skid package under water and the ROV can be quickly removed or installed on the subsea drilling system while on the deck of a support vessel.
With the foregoing and other objects in view there is provided, in accordance with the invention, a subsea drilling system. The system comprises a drilling module having a tool carousel being removable and replaceable in or out of water, a skid module, and an ROV to be connected to and disconnected from the skid module in or out of water for operating the subsea drilling system with the ROV.
With the objects of the invention in view, there is also provided a method for operating a subsea drilling system. The method comprises removing a tool carousel from a drilling module and replacing the tool carousel with another tool carousel, in or out of water, connecting an ROV to a skid module and disconnecting the ROV from the skid module in or out of water, and operating the subsea drilling system with the ROV.
The subsea drilling system according to the invention is constructed for taking geological core samples by using conventional diamond drilling techniques in water depths of 3000 meters or 9840 feet. The system is configured in conjunction with a heavy duty work class ROV of opportunity and utilizes terrestrial drilling and coring technology. A conventional coring tool and drilling system is used along with a reverse circulation drilling system.
Two major assemblies or packages are provided within the subsea drilling system, that is a subsea drilling package and a surface controls package. The subsea drilling system according to the invention may interface with an ROV of opportunity, such as a Triton ST 200 class ROV. The subsea drilling system operates by employing the ROV of opportunity to supply a communications link for hydraulic and electrical power. The subsea drilling system uses the ST 200 class ROV, or any work class ROV, to define supplies, services and operations.
The functional system performance requirements for a baseline subsea drilling system are a coring depth of 12 meters or 39.4 feet and a core density assumed to be at a specific gravity of 3.5. The core diameter and length have a nominal size of 51.8 millimeters or 2.04 inches by 1.5 meters or 59 inches, per barrel. The drilling feed force will be 0 to 40 kilonewtons, which is 9,000 pounds per foot, and the retraction force is the same.
The pipe rod handling capability accommodates rods of 2.0 meters or 79 inches in length plus one joint make or break per minute. The rod running speed for feed and retraction is 0 to 0.2 meters or 0.66 feet per second with no load and 0 to 0.025 meters or 1 inch per second under a load of 40 kilonewton or 9,000 pounds per foot. The drilling head travels down at a speed of 15.2 meters or 50 feet per minute and up at a speed of 10.7 meters or 35 feet per minute. The drill torque range is 15 Newton-meters to 250 Newton-meters or 11 foot pounds to 185 foot pounds. The drill speed range is 0 to 900 rpm, continuously variable, using a two-speed motor and the maximum drill spindle speed is 1200 rpm.
The subsea drilling system structure is configured in accordance with Det Norske Veritas or DNV Rules for Certification of Lifting Appliances and the load test was witnessed by the DNV.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a subsea drilling system and a method for operating the subsea drilling system, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a chart showing the components of the subsea drilling system according to the invention;

FIG. 2A is a diagrammatic, front and side perspective view of a subsea skid package, including a drilling module and a skid module;

FIG. 2B is a front and side perspective view of an ROV;

FIG. 2C is a front and side perspective view of the drilling module and the skid module with the ROV installed;

FIG. 3 is a front and side perspective view similar to FIG. 2C, with legs extended and illustrating a drill head assembly and tool carousel;

FIG. 4 is an enlarged, elevational view of the drill head assembly;

FIG. 5 is a further enlarged, cross-sectional view of the drill head assembly;

FIG. 6 is an even further enlarged, cross-sectional view of the drill head assembly;

FIG. 7 is a top perspective view of the tool carousel in the drilling module;

FIGS. 8 and 9 are differently enlarged, elevational views of the tool carousel;

FIG. 10 is an elevational view of the tool carousel with a carousel pin receptacle;

FIG. 11 is a perspective view of a drive mechanism;

FIG. 12 is a perspective view of a foot clamp;

FIG. 13 is a perspective view of a tool arm in a retracted position;

FIG. 14 is a perspective view of the tool arm in an extended position;

FIG. 15 is an enlarged, perspective view of a gripper of the tool arm;

FIGS. 16, 17 and 18 are respective outer-perspective, inner-elevational and enlarged, fragmentary, inner-elevational views of a leveling leg;

FIG. 19 is a front and side perspective view of a structural frame for the drilling module;

FIG. 20 is a perspective view of a drilling water pump;

FIGS. 21-23 are schematic diagrams of hydraulic systems of drilling module manifolds;

FIG. 24 is a schematic diagram of electric cabling and subsea controls;

FIG. 25 is a perspective view of a structural frame for the skid module;

FIG. 26 is a perspective view of a surface controls station;

FIGS. 27A, 27B and 28 illustrate a main drilling screen, a tool change screen and a data logger;

FIG. 29 is a perspective view of a reverse-circulation drilling head;

FIG. 30 is a fragmentary, perspective view of a circulation drilling bit; and

FIGS. 31 and 32 are enlarged, fragmentary, perspective views of portions of the circulation drilling bit.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a chart showing the components of the subsea drilling system according to the invention, including a subsea skid package and a surface controls package, which will be explained in detail below.
FIG. 2A shows the subsea skid package, which includes a drilling module 1 and a skid module 100. FIG. 2B shows an ROV 3 to be used with the subsea skid package, and FIG. 2C shows the ROV 3 installed on the subsea skid package. The ROV of opportunity illustrated in this case is an XLXS 125, although others may be used instead. The drilling module 1 has two stabilization and leveling legs 80 and the skid module 100 has one stabilization and leveling leg 80, in a modified tripod configuration. The legs 80 may be extended as shown in FIG. 2A, retracted as shown in FIG. 2C, or partially extended to compensate for unevenness of the seafloor. The legs 80 have a maximum extension of 53″, although they could be constructed for a longer or shorter maximum extension. Two tool arms 70 and a drilling head 10, which will be explained in greater detail below, can also be seen in FIG. 2C. FIG. 3, which also shows the legs 80 extended, shows the drilling head 10 deployed down, whereas it is deployed up in FIG. 2C. Finally, FIGS. 2A, 2C and 3 also show a structural frame 90 for the drilling module 1 and a structural frame 130 for the skid module 100.
The ROV shown in FIGS. 2B, 2C and 3 is an ROV of opportunity that can be mated at subsea with the subsea drilling system. The subsea drilling system itself cannot be operated alone, but instead is operated by the ROV. There is also the possibility of using several subsea drills on the bottom with one ROV that can travel from one subsea drilling system to another and operate it in various configurations. The ROV has mating pins and a wet mate connector at locations 12, which can make electrical, hydraulic and communications connections to the vehicle to operate the subsea drilling system.
The subsea drilling system is a drilling and coring system. The general requirements of the system call for the ROV to supply hydraulic and electric power, telemetry and spare fiber. The system is capable of drilling and recovering cores of 20 meters with the illustrated configuration and diamond drilling tools. A specialized core barrel system referred to as the ROV 275 Core Barrel and Rod Assembly is used. The XLS 125 ROV is used for a baseline system, although many other types of heavy work class ROVs can be used with the subsea drilling system according to the invention. The system uses two packages, namely a surface controls package and a subsea skid package having the drilling module 1, as is seen in FIG. 1.
FIG. 4 is an enlarged view showing more detail of the drilling head 10 of the drilling module 1, which can be seen to include an aluminum cross beam 14, two hydraulic elevator cylinders 15, 16, a spindle assembly 18, a hydraulic spindle drive motor 19 and a non-metallic spindle drive belt 20.
Even greater detail concerning the drilling head 10 is provided by the cross-sectional view of FIG. 5. It may be seen therein that the spindle assembly 18 has a spindle 21, a spindle lock cylinder 22, a water swivel 23 and a saver sub 24. The spindle lock cylinder 22 locks the cylinder so that it can be used for torquing applications. The water swivel 23 is where water enters into the drilling head 10 and down into a drill pipe for lubricating a hole being drilled and cleaning out shavings. The saver sub 24 connects to the drill pipes or to a core barrel for drilling. The hydraulic spindle drive motor 19 is connected to an overhung motor adapter 26 and to a drive sprocket 27 using the non-metallic spindle drive belt 20.
A further enlarged view of the spindle assembly 18 shown in FIG. 6 again indicates the spindle 21, the spindle lock cylinder 22, the water swivel 23 and the replaceable saver sub 24. The spindle 21 has four spindle detents 29, eight spindle drive balls 30 and a spindle lock cylinder having a spindle sprocket 25 and a spindle lock spring 28. A ball actuation line 31 leads to a part that can be pressurized and has a slide 36 that can slide up to push the balls inward and lock them against the spindle 21. The drilling head 10 also includes upper ball bearings 32 and lower ball bearings 33 to take up loads in either direction from drilling applications. Upper bearing compensator lines 34 are provided for adding oil into the bearings to keep the sea water out. A non-illustrated RPM sensor, which is installed at a location 35, measures the RPM of the drilling head 10.
FIG. 7 illustrates a tool carousel 40, which is part of the drilling module 1. The tool carousel 40 is supported by a drilling module frame 90, which also holds the drilling head 10, shown in the upper or raised position. The tool carousel 40 is a cylindrical configuration that has twelve slots which can carry tools. Each slot can carry two tools, providing possibility of using up to 24 tools in the tool carousel 40.
FIGS. 8 and 9 are enlarged to show more detail of the tool carousel 40. The bottom of the tool carousel 40 has a drive wheel 43 which drives the carousel from slot to slot, as an indexing drive wheel. It may be seen that drilling tools 45, 46 are located in respective slots and held by tool retention fingers 76. The drilling tools also include core barrels, which may be disposed on the carousel, as will be described below. Although there are twelve slots, as mentioned above, one slot is kept blank leaving eleven slots available for use with up to twenty-two drilling tools 45, 46. One slot is left vacant to prevent the tools 45, 46 from falling out of the carousel 40 during launch and recovery operations. The carousel 40 has an upper retaining ring 42 with an opening formed therein for accessibility to allow the tools 45, 46 to be taken in and out of the carousel 40. The carousel 40 also has a lifting eye 43 and carousel guide receptacles 44, only one of which is shown in FIG. 9, that mate with upper guide pins on the frame 90, as is seen in FIG. 7. A lower retaining ring, which is also present, is discussed below. The carousel can be pulled and replaced in one piece subsea, by using the lifting eye 43 and leaving the drive assembly down on the subsea drilling system, so that the carousel can be replaced with a different carousel if needed to carry additional tools or continue to drill to deeper hole configurations.
FIG. 10 is an enlarged view of the lower portion of the tool carousel 40, which can be pulled subsea and replaced with another carousel depending on the operations carried out by the operator of the system at that time. Reference numeral 48 indicates the lower retaining ring having lower guide pin receptacles 49 for receiving lower guide pins 51. A guide pin receptacle 53, which is part of the carousel 40 itself, receives a square male drive pin 54 that is part of a drive mechanism 50. When the carousel 40 is slid down, the lower guide pins 51 orient the bottom of the carousel, while the upper guide pins orient the top of the carousel, as is seen in FIG. 7. The carousel sits on these guide pins and can be operated by the drive system. When the carousel is pulled, the square drive pin 54 is separated from the receptacle 53, the guide pins 51 on the bottom are separated from the receptacles 49 and the guide pins on the top are separated from their receptacles.
FIG. 11 illustrates the drive mechanism 50, that employs a well-known Geneva drive assembly used for indexing drives, for driving the tool carousel 40. The drive mechanism 50 has a Geneva drive motor 55 which rotates through 360 degrees. An oil-compensated motor mount adapter 56 rests above the drive motor 55 and a Geneva drive wheel 58, driven by the motor 55, carries the drive pin 54 to be connected to and disconnected from the tool carousel 40. The drive wheel 58 indexes one-twelfth of its circumference upon each rotation of the motor 55. The indexing is carried out by a pin 59 having a shaft which is engaged in slots 57.
FIG. 12 shows a foot clamp assembly 60 of the drilling module 1. The foot clamp assembly 60 includes an upper foot clamp 62, shown with its cover removed, and a lower foot clamp 64, which are separated by a plate 65 mounted on the frame. The upper foot clamp 62 has foot clamp grip cylinders 66, 67 and gripper slide bearings 68. The lower foot clamp also uses cylinders identical to the cylinders 66, 67 and slide bearings identical to the slide bearings 68. The foot clamp assembly 60 functions to grab a pipe and to make and break joints. A rotation cylinder 69 is used to rotate the upper foot clamp 62, which can be mounted on a bearing and can be rotated up to 100 degrees by a hydraulic cylinder used to make and break joints. The lower foot clamp 64 does not rotate, but instead is static and mounted to the frame. The foot clamps that are used are special grips, which are formed of high-strength, very hard material and are used to grab the pipe.
A fail-safe feature causes the jaws to open with the hydraulics off. The jaws are constructed for a tool size grip range between 25 and 70 mm, with another set of jaws being required for larger sizes up to 89 mm. A maximum pass through opening is set at 108 mm. The torque capability is up to 1,000 foot pounds.
FIG. 13 illustrates one of two tool arms 70 of the drilling module 1 shown in FIGS. 2C and 3. The upper tool arm 70 is a grabber tool arm and the lower tool arm 70 is an alignment tool arm. The tool arms 70, which can be operated by hydraulics, either independently or together, each include a gripper arm 72 and a mounting bracket 74. The tool arms 70 are used to resist the maximum torque generated by the drilling head 10 and are used to tighten and loosen the tool joint at the spindle. The tool arms 70 therefore have an extension with a gripper 76. The lower alignment tool arm 70 is used for positioning the tool relative to a centerline of the foot clamp assembly 60. An energy chain 73 for translating hoses is provided on the gripper arm 72. Whereas FIG. 13 shows the gripper arm 72 retracted, FIG. 14 shows it extended. It is seen from the enlarged view of FIG. 15 that the gripper 76 of the grabber tool arm has carbide inserts 77, whereas plastic inserts are provided on the lower or alignment tool arm.
The tool arm 70 is made out of aluminum and is operated by a hydraulic cylinder, so that it can be pushed and slid in and out. The gripping function, which is accomplished by opening and closing the jaws 76, is also hydraulic. There is additionally a bump function, which can move the arm sideways up to an inch in either direction to aid in fine alignment.
The stabilization and leveling legs 80, which are shown in FIGS. 16-18, have outer cylinders 82 which are attached by adjustable clamps to the frame and inner cylinders 84 which can be extended and retracted hydraulically within the outer cylinders 82. The inner cylinders 84 also have detachable leg pads 86. Two slide bearing ring assemblies 87 take up sliding loads when the leg 80 is extended or retracted. Once again, the function of the legs 80 is to raise and lower the level of the entire system during operation subsea. The legs can be used to level the system once its subsea under various terrain conditions, up to an angle of 20 degrees.
FIG. 19 illustrates the structural frame 90 for the drilling module 1, which has removable guide beams 92, slides and rollers for travel of the drilling head 10. The frame 90 is made out of aluminum, welded top and bottom, with bolted vertical members, and is load tested to 3Gs (three times the force of gravity).
FIG. 20 shows a drilling water pump 102 of the skid module 100, which forms the subsea skid package along with the drilling module 1. The drilling water pump 102 is a conventional, off-the-shelf piece of equipment, which is driven by hydraulic motor. The drilling water pump 102 is used to run water down along the drill pipe to the drill bits, where it can be used to flush out drill shavings.
FIGS. 21, 22 and 23 are diagrams of respective hydraulic systems 105, 110 and 115 of drilling module manifolds 1, 2 and 3, which are powered by a hydraulic system on an ST 200 ROV. In other words, the ROV will operate hydraulic functions by supplying hydraulic fluid to the subsea drilling system and then back again to the ROV. Three to nine function control manifolds that are used for controlling the subsea drilling system are mounted on the subsea drilling system.
More specifically, FIG. 21 shows a general overall view of the hydraulic system 105 in the manifold 1, which is the first of the three manifolds having a first four motion controls that are used, as seen from left to right, for drill feed, drill head up and down and elevator drilling controls. The fifth control is for the carousel motor. The balance of the last four hydraulic controls are used for the foot clamps and spindle lock.
FIG. 22 shows the hydraulic system 110 in the manifold 2. Again, the first two valves from left to right are used for controlling the speed of the hydraulic motor that drives the spindle. The third valve is for the shift speed, which is used to control either high or low shifting of the hydraulic motor. The other valves are used for grippers or grabbers, alignment arms and bump functions, basically for the tool arms.
FIG. 23 shows the hydraulic system 115 in the manifold 3, which controls the skid and options. The first valve is blanked off. The second valve is used for controlling the motor of the water pump, which is used for sending water down the drill string to the drill bits. The other three valves are used for the stabilization legs and can be used to move the legs up or down.
FIG. 24 shows an electric cabling diagram 120 and subsea controls 125. The cabling diagram is basically similar to the hydraulic system and has controls for all three of the manifolds, that is the manifolds 1 and 2 and the skid manifold 3. The diagram shows various sensors and various applications. Inside each of these manifolds is a Perry Slingsby smart valve pack controller or LCV (local valve controller). Each of the boards will control specific functions within its manifold.
FIG. 25 shows the structural frame 130 for the skid module 100, which is constructed for various interfaces. The illustrated structural frame 130 is particular provided for interface with the ST 200 ROV. The structural frame 130 is again made out of aluminum welded frames and tested to 3Gs.
FIG. 26 shows that the surface controls package has surface controls 140 including a stand-alone console having a rack mount 141 with a display 142, an angled control panel 145 with two drilling joy sticks, a 19 inch touch screen LCD color monitor 143, an IBM Blade computer 144 with a USB interface to equipment, an RS 232 to RS 485 converter, a keyboard and a mouse. Different pages, which are displayed, are used for setting up, landing and operating the system.
FIGS. 27A and 27B illustrate examples of a main drilling screen and a tool change screen of the surface controls 140, which are displayed on the touch screen monitor. All of the software which is used, is integrated within the system.
FIG. 28 illustrates a data logger of the surface controls 140 showing an example of how functions are logged and saved during drilling operations. Logging is used subsequently by geologists after the hole is drilled, to validate that the drilling processes have been carried out successfully.
FIG. 29 shows a configuration used for reverse circulation drilling, which is different than conventional drilling, because it uses reverse circulation of water. Water is sent down through the outside of the drilling tool annular section and pulled up through the center. Basically, reverse circulation drilling takes drilling cuttings and instead of feeding them into a core barrel, pulls them into a catchment bag assembly.
A comparison of FIG. 4 with FIG. 29 shows what needs to be done to the drilling head 10 to convert it for reverse circulation. A second swivel 131 is added, as well as a goose neck or hose connection 132 leading to a sample catchment bag. The reverse circulation drilling uses different drilling tools, namely RCD (Reverse Circulation Drilling) drill rods 133 and different bits.
FIG. 30 is an enlarged view showing the RCD drill rod 133 and an RCD drilling bit 134. It is seen that an outer tube 136 and an inner tube 137 are provided, through which water flows in the direction of the arrows. The arrows indicate that water is pushed down through the outer tube 136 and then into the drill bit 134, and the water is then pulled back up through the center of the inner tube 137 and through the connection 132 into the catchment bag.
FIGS. 31 and 32 are further enlarged to show more detail of the dual tube or reverse circulation tube configuration 136, 137 and the drill 134 bit, respectively.

Claims

1. A subsea drilling system, comprising:

a drilling module having a tool carousel being removable and replaceable in or out of water;

a skid module; and

an ROV to be connected to and disconnected from said skid module in or out of water for operating the subsea drilling system with said ROV.

2. The subsea drilling system according to claim 1, wherein said drilling module has a structural frame, and said tool carousel is guided into place on said structural frame by pins and guide receptacles.

3. The subsea drilling system according to claim 2, wherein said tool carousel is removable and replaceable under water by another ROV.

4. The subsea drilling system according to claim 2, wherein one of said pins drives said tool carousel.

5. The subsea drilling system according to claim 1, wherein said tool carousel has slots for receiving drilling tools.

6. The subsea drilling system according to claim 1, wherein said drilling module has a drilling head with a spindle assembly and a drive motor for driving drill rods, and said drilling head is moveable up and down on hydraulic elevator cylinders.

7. The subsea drilling system according to claim 1, wherein said drilling module has foot clamps for grasping pipes and making and breaking joints.

8. The subsea drilling system according to claim 5, wherein said drilling module has tool arms for inserting said drilling tools into and removing said drilling tools from said slots.

9. The subsea drilling system according to claim 1, wherein said drilling module has a structural frame, said skid module has a structural frame, and stabilization and leveling legs are attached to said frames to compensate for uneven terrain under water.

10. The subsea drilling system according to claim 1, wherein said skid module has a water pump for running water along a drill pipe to drill bits for flushing out drill shavings.

11. The subsea drilling system according to claim 1, wherein said skid module has a structural frame with for receiving said ROV.

12. The subsea drilling system according to claim 11, wherein said structural frame has pins and a connector for said ROV.

13. The subsea drilling system according to claim 1, which further comprises a surface controls package having a display, a monitor, a computer and interfaces for remotely controlling the subsea drilling system.

14. The subsea drilling system according to claim 6, wherein said drill rods are reverse circulation drill rods, and a swiveling hose is connected to said spindle assembly and leads to a catchment bag, for reverse circulation drilling.

15. A method for operating a subsea drilling system, the method comprising the following steps:

removing a tool carousel from a drilling module and replacing the tool carousel with another tool carousel, in or out of water;

connecting an ROV to a skid module and disconnecting the ROV from the skid module in or out of water; and

operating the subsea drilling system with the ROV.

16. The method according to claim 15, which further comprises guiding the tool carousel into place on a structural frame of the drilling module with pins and guide receptacles.

17. The method according to claim 15, which further comprises carrying out the step of removing and replacing the tool carousel under water with another ROV.

18. The method according to claim 15, which further comprises driving the tool carousel with one of the pins.

19. The method according to claim 15, which further comprises placing drilling tools into and removing the drilling tools from, slots in the tool carousel.

20. The method according to claim 15, which further comprises driving drill rods with a spindle assembly and a drive motor on a drilling head of the drilling module, and moving the drilling head up and down on hydraulic elevator cylinders.

21. The method according to claim 15, which further comprises grasping pipes and making and breaking joints with foot clamps of the drilling module.

22. The method according to claim 19, which further comprises inserting the drilling tools into and removing the drilling tools from the slots with tool arms of the drilling module.

23. The method according to claim 15, which further comprises compensating for uneven terrain under water with stabilization and leveling legs attached to structural frames of the drilling module and the skid module.

24. The method according to claim 15, which further comprises running water along a drill pipe to drill bits for flushing out drill shavings with a water pump of the skid module.

25. The method according to claim 15, which further comprises mating the ROV to pins and a connector on a structural frame of the skid module.

26. The method according to claim 15, which further comprises remotely controlling the subsea drilling system with a surface controls package having a display, a monitor, a computer and interfaces.

27. The method according to claim 15, which further comprises guiding drilling cuttings from reverse circulation drill rods, through a spindle assembly and a swiveling hose into a catchment bag, for reverse circulation drilling.