Subsea Drilling System and Method for Operating the Drilling System

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.

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.