Drilling rig

Abstract

An underwater drilling rig in modular form, which can be simply assembled underwater and in which standard tubulars and tubular assemblies are stored in a novel arrangement within containers and can be added to, and removed from, the string in the well bore, whilst there is continuous circulation of drilling fluid and also continuous segregation of drilling fluid from the seawater, additionally: with a simple means of accessing the tubulars and gripping them from inside in order to make up tool joint connection to the top drive sub, with a means to guide and centralise each tubular or tubular assembly on entering the well bore or when being returned to storage with a means to enable the top drive to snub with greatly reduced force and no risk of buckling the tubular, with a rig support vessel that, in the absence of a marine riser, drill string or drilling rig, is greatly reduced in size and can roam extensively to ride out bad weather, while the seabed rig continues to drill; lastly with the novel ability to control the mud pressure and flow both in and out of the well bore at seabed level, thus greatly improving downhole pressure strategy, ultimately the first system that can operate at water depths of 10,000 to 20,000 feet which is still beyond the current economic and technical ability of offshore drilling rigs.

1 - 26 . (canceled)  
   
   
       27 . A drilling rig for use underwater which comprises: 
 (i) a stinger that can access stored tubulars and can convey mud into the string;    (ii) a storage system for all tubulars and tubulars assemblies;    (iii) a drilling mast that carries the stinger and is able to move laterally between the well bore centre and the storage location of each tubular or tubular assembly in the storage system;    (iv) a continuous circulation coupler which is able to segregate the seawater from the drilling fluids and can make and break the tool joint connections under pressure; and    (v) an assembly means which can launch and retrieve the rig from rig support vessel and can assemble and disassemble the rig at the seabed.    
   
   
       28 . A drilling rig according to  claim 27  in which the stinger is adapted to provide internal support for a tubular to guide it and/or centralize it when entering a well bore, drilling equipment or storage location and the stinger can grip a tubular or tubular assembly from the inside, while another tubular is connected and torqued up.  
   
   
       29 . A drilling rig according to  claim 27  in which the stinger is adapted to resist the internal pressure of a well bore or drilling equipment, while a tubular is slid off the stinger into the said well bore or drilling equipment.  
   
   
       30 . A drilling rig according to  claim 27  in which there is at least one container that serve to store at least some of the tubulars and/or tubular assemblies such that each said tubular and/or tubular assembly is allocated a designated storage location.  
   
   
       31 . A drilling rig according to  claim 30  in which in use the containers are adapted to perform their function in the vertical or any other angle in addition to the horizontal orientation or aspect.  
   
   
       32 . A drilling rig according to  claim 30  in which the containers are adapted so that they can be connected to each other such that one container can support the weight of another full container, when both are parallel but not in the conventional substantially horizontal plane.  
   
   
       33 . A drilling rig according to  claim 27  in which the stinger is attached to a carriage or mechanism mounted on the mast stinger such that the stinger can be moved in an out of a tubular.  
   
   
       34 . A drilling rig according to  claim 30  in which the stinger is attached to a carriage or mechanism mounted on the mast stinger can be moved in and out of a tubular.  
   
   
       35 . A drilling rig according to  claim 27  in which there is top drive mounted on the mast that is moved along the length of the mast by a carriage or mechanism mounted on the mast.  
   
   
       36 . A drilling rig according to  claim 35  in which both the stinger and top drive are mounted on the mast such that the mud supply is to the stinger and the top drive seals to the exterior surface of the stinger.  
   
   
       37 . A drilling rig according to  claim 35  in which there are means to move the mast laterally such that it can be made to line up with a tubular or tubular assembly that may or may not be on the centre line of the well bore.  
   
   
       38 . A drilling rig according to  claim 27  in which the continuous circulation coupler is able to connect and disconnect tubulars from a drill string whilst there is continuous circulation of mud or drilling fluid down the drill string.  
   
   
       39 . A drilling rig according to  claim 30  in which the continuous circulation coupler is able to connect and disconnect tubulars from a drill string whilst there is continuous circulation of mud or drilling fluid down the drill string.  
   
   
       40 . A drilling rig according to  claim 27  in which the continuous circulation coupler is able to connect and disconnect tubulars from a drill string whilst the drill string is rotated.  
   
   
       41 . A drilling rig according to  claim 40  in which there is a drilling mast module mounted on a wellhead module, which is mounted on a foundation conductor that has been driven or drilled into the seabed.  
   
   
       42 . A drilling rig according to  claim 41  in which the wellhead module laterally supports a power module and a mud module and a-number of pipe modules which can store tubulars and tubular assemblies.  
   
   
       43 . A drilling rig according to  claim 27  in which there is a submerged power module that provides electrical and/or hydraulic power to all other modules by transferring and transforming and/or storing electrical power from an electric cable from the rig vessel.  
   
   
       44 . A drilling rig according to  claim 38  in which there is a submerged power module that provides electrical and/or hydraulic power to all other modules by transferring and transforming and/or storing electrical power from an electric cable from the rig vessel.  
   
   
       45 . A drilling rig according to  claim 27  in which there is a submerged mud module that is able to choke or otherwise control the pressure and/or flow of the mud entering the drill string substantially at the level of the seabed.  
   
   
       46 . A drilling rig according to  claim 38  in which there is a submerged mud module that is able to choke or otherwise control the pressure and/or flow of the mud entering the drill string substantially at the level of the seabed.  
   
   
       47 . A drilling rig according to  claim 45  in which there is a separate cuttings module or container which can be returned periodically to the drill vessel and a mud module which can transfer concentrated drill cuttings to the separate cuttings module or container.  
   
   
       48 . A drilling rig according to  claim 27  in which the assembly means comprises a driving module which can drive in a foundation conductor either by the diving module with the power module attached, or drilled in by a mast module with the power module and a pipe module attached.  
   
   
       49 . A drilling rig according to  claim 27  in which there is a submerged well head module that integrates a BOP stack, rotary BOP, slips and continuous circulation and/or rotation coupler into one unit.  
   
   
       50 . A drilling rig according to  claim 27  in which there are means to connect the rig to a rig vessel by flexible umbilicals, or risers in order to be able to transfer all of the necessary power, mud and instrumentation between the rig vessel and the rig.  
   
   
       51 . A drilling rig according to  claim 27  in which there is a submerged generator or a power pack to supply power and means to recondition mud for re-use on the seabed, and means for containerizing and regularly removing cuttings and a means to remotely control the drilling operation such that a rig vessel is not required to be permanently located substantially above the seabed rig.