Ocean floor deep-sea submerged deck

Abstract

A system for drilling a deep-sea borehole in a seabed is provided. The system includes a drill string having a plurality of strands adapted to be reversibly connected together to assemble the drill string and reversibly disconnected from one another to disassemble the drill string. The system further includes a submerged drilling deck anchored on the seabed, the deck adapted to reversibly connect the strands together and to reversibly disconnect the strands from one another. Methods of disassembling and assembling the drill string are also provided.

1 . A system for drilling a deep-sea borehole in a seabed, the system comprising:
 a drill string comprising a plurality of strands adapted to be reversibly connected together to assemble the drill string and reversibly disconnected from one another to disassemble the drill string; and   a submerged drilling deck anchored on the seabed, the deck adapted to reversibly connect the strands together and to reversibly disconnect the strands from one another.   
     
     
         2 . The system of  claim 1 , wherein the deck is adapted to be controlled remotely from a vessel at the ocean surface or from a remotely operable underwater vehicle. 
     
     
         3 . The system of  claim 1 , wherein the plurality of strands comprises a first strand extending above the deck and a second strand below the first strand and extending below the deck, wherein the deck is adapted to substantially rotate one of the first strand and the second strand about its axis while the other of the first strand and the second strand is not substantially rotated about its axis. 
     
     
         4 . The system of  claim 1 , wherein one or more of the strands has a length greater than 1000 meters. 
     
     
         5 . The system of  claim 1 , wherein the plurality of strands comprises a drill bit. 
     
     
         6 . The system of  claim 1 , further comprising a riser adapted to allow a drilling fluid to flow through the riser, wherein a first end portion of the riser is operatively coupled to the deck and a second end portion of the riser is operatively coupled to a vessel at the ocean surface. wherein the drill string is adapted to pass through the riser. 
     
     
         7 . The system of  claim 6 , wherein the deck comprises a cabinet having a top portion and a bottom portion, the top portion operatively coupled to the first end portion of the riser, the bottom portion operatively coupled to the borehole, wherein the drill string is adapted to pass through the riser, through the cabinet, and into the borehole. 
     
     
         8 . The system of  claim 7 , wherein the deck further comprises a conduit adapted to allow drilling fluid to flow through the conduit and to operatively couple the bottom portion of the cabinet to the borehole, wherein the drill string is adapted to pass through the conduit. 
     
     
         9 . The system of  claim 7 , wherein the riser and the top portion of the cabinet are adapted to be spaced from and moved relative to the bottom portion of the cabinet while a first strand of the plurality of strands extends within the riser above the top portion of the cabinet and a second strand of the plurality of strands extends within the borehole below the bottom portion of the cabinet. 
     
     
         10 . The system of  claim 1 , wherein the deck further comprises a drilling motor configured to be remotely controlled from a position away from the deck. 
     
     
         11 . The system of  claim 1 , further comprising:
 a second drill string comprising a second plurality of strands adapted to be reversibly connected together to assemble the second drill string and reversibly disconnected from one another to disassemble the second drill string; and   a second submerged drilling deck anchored on the seabed at a position spaced from the deck, the second deck adapted to reversibly connect the second plurality of strands together and to reversibly disconnect the second plurality of strands from one another, wherein the deck and the second deck are both adapted to be controlled remotely from a single vessel at the ocean surface.   
     
     
         12 . A method of disassembling a drill string comprising a plurality of strands, the drill string extending into a deep-sea borehole in a seabed, the method comprising:
 providing a submerged drilling deck anchored on the seabed;   positioning the drill string such that a first strand of the plurality of strands extends above the deck and a second strand of the plurality of strands extends below the deck into the borehole, the first strand comprising a first end portion and a second end portion and the second strand comprising a first end portion and a second end portion, the first end portion of the first strand connected to the second end portion of the second strand; and   using the deck to reversibly disconnect the first end portion of the first strand from the second end portion of the second strand.   
     
     
         13 . The method of  claim 12 , further comprising suspending the second end portion of the first strand from a vessel at the ocean surface while using the deck to reversibly disconnect the first end portion of the first strand from the second end portion of the second strand. 
     
     
         14 . The method of  claim 12 , further comprising suspending the second end portion of the first strand from a vessel at the ocean surface after using the deck to reversibly disconnect the first end portion of the first strand from the second end portion of the second strand. 
     
     
         15 . The method of  claim 12 , wherein the first strand has a length greater than 1000 meters and the second strand has a length greater than 1000 meters. 
     
     
         16 . The method of  claim 12 , wherein the drill string passes through a riser adapted to allow a drilling fluid to flow through the riser, wherein a first end portion of the riser is operatively coupled to the deck and a second end portion of the riser is operatively coupled to a vessel at the ocean surface. 
     
     
         17 . The method of  claim 16 , wherein the deck comprises a cabinet having a top portion and a bottom portion, the top portion operatively coupled to the first end portion of the riser, the bottom portion operatively coupled to the borehole, wherein the drill string is adapted to pass through the riser, through the cabinet, and into the borehole. 
     
     
         18 . The method of  claim 17 , wherein using the deck to reversibly disconnect the first end portion of the first strand from the second end portion of the second strand comprises:
 positioning the first end portion of the first strand and the second end portion of the second strand within the cabinet;   forming at least one first seal to substantially contain drilling fluid within the riser;   forming at least one second seal to substantially contain drilling fluid within the borehole;   removing drilling fluid from the cabinet between the at least one first seal and the at least one second seal; and   reversibly disconnecting the first end portion of the first strand from the second end portion of the second strand.   
     
     
         19 . The method of  claim 16 , further comprising:
 forming at least one seal to substantially contain drilling fluid within the first strand;   forming at least one seal to substantially contain drilling fluid within the second strand;   reversibly detaching the top portion of the cabinet from the bottom portion of the cabinet; and   moving the first strand, the riser, and the top portion of the cabinet away from the second strand.   
     
     
         20 . The method of  claim 19 , further comprising suspending the second end portion of the second strand from the vessel and raising the second strand out of the borehole. 
     
     
         21 . The method of  claim 16 , further comprising:
 forming at least one seal to substantially contain drilling fluid within the first strand;   forming at least one seal to substantially contain drilling fluid within the second strand;   suspending the second end portion of the second strand from the vessel and raising the second strand out of the borehole and into the riser.   
     
     
         22 . A method of assembling a drill string for drilling a deep-sea borehole in a seabed, the method comprising:
 providing a submerged drilling deck anchored on the seabed;   providing a plurality of drill string strands comprising a first strand comprising a first end portion and a second end portion and a second strand comprising a first end portion and a second end portion; and   using the deck to reversibly connect the first end portion of the first strand to the second end portion of the second strand.   
     
     
         23 . The method of  claim 22 , further comprising suspending the second end portion of the first strand from a vessel at the ocean surface while using the deck to reversibly connect the first end portion of the first strand to the second end portion of the second strand. 
     
     
         24 . The method of  claim 22 , further comprising suspending the second end portion of the first strand from a vessel at the ocean surface before using the deck to reversibly connect the first end portion of the first strand to the second end portion of the second strand. 
     
     
         25 . The method of  claim 22 , wherein the first strand has a length greater than 1000 meters and the second strand has a length greater than 1000 meters. 
     
     
         26 . The method of  claim 22 , wherein the first strand passes through a riser adapted to allow a drilling fluid to flow through the riser, wherein a first end portion of the riser is operatively coupled to the deck and a second end portion of the riser is operatively coupled to a vessel at the ocean surface. 
     
     
         27 . The method of  claim 26 , wherein the deck comprises a cabinet having a top portion and a bottom portion, the top portion operatively coupled to the first end portion of the riser, the bottom portion operatively coupled to the borehole, wherein the drill string is adapted to pass through the riser, through the cabinet, and into the borehole. 
     
     
         28 . The method of  claim 27 , wherein using the deck to reversibly connect the first end portion of the first strand to the second end portion of the second strand comprises:
 positioning the first end portion of the first strand and the second end portion of the second strand within the cabinet, wherein at least one first seal around the first strand substantially contains drilling fluid within the riser and at least one second seal around the second strand substantially contains drilling fluid within the borehole;   reversibly connecting the first end portion of the first strand to the second end portion of the second strand;   closing the cabinet and filling the cabinet with drilling fluid between the at least one first seal and the at least one second seal; and   opening the at least one first seal and opening the at least one second seal to allow drilling fluid to flow through the borehole, the cabinet, and the riser.