Well drilling and production using a surface blowout preventer

Abstract

Production and drilling may be achieved by a system which uses a rotating head coupled to surface blowout preventer stack for fluid flow control. A casing connects these surface components to a subsea shutoff assembly with a pair of ram shear devices to cut off the string to the wellhead. Both the casing and an alternate line may be latched so that they may be released if necessary. The rotating head may include a rubber packer to prevent upward flow of drilling fluid and production hydrocarbons and, at the same time, provide rotation to the drill string. Managed pressure drilling or under balanced drilling may be used in some embodiments.

1 . A method comprising: 
 producing hydrocarbons from a subsea well using a rotating head mounted on a surface blowout preventer and injecting a density lowering fluid through the drill string and the surface blowout preventer.    
   
   
       2 . The method of  claim 1  including using the surface blowout preventer to provide surface flow control.  
   
   
       3 . The method of  claim 2  including providing a subsea shutoff assembly in addition to said surface blowout preventer.  
   
   
       4 . The method of  claim 3  including providing shear and emergency disconnect capability in the event the well control is lost.  
   
   
       5 . The method of  claim 1  including coupling said surface blowout preventer to a wellhead using a connector and providing a remotely operable subsurface latch to sever the connection between said wellhead and said surface blowout preventers.  
   
   
       6 . The method of  claim 5  including tensioning said casing.  
   
   
       7 . The method of  claim 5  including providing a flow of mud through a casing to a drill bit.  
   
   
       8 . The method of  claim 7  including lowering the density of mud by beginning the injection of said density lowering fluid when production begins.  
   
   
       9 . The method of  claim 1  including providing a rotating head that transfers rotational energy to said drill string through a packer.  
   
   
       10 . The method of  claim 9  including providing said rotational energy through a resilient packer.  
   
   
       11 . The method of  claim 1  including drilling under-balanced.  
   
   
       12 . The method of  claim 1  including using managed pressure drilling.  
   
   
       13 . A drilling rig comprising: 
 a rotating head;    a drill string coupled to said rotating head;    a surface blowout preventer mounted under said rotating head on said rig; and    an apparatus to pump lower density drilling mud to the bottom of a hole through said drill string and drill bit.    
   
   
       14 . The rig of  claim 13  including a connector coupled from said surface blowout preventer to a subsea shutoff assembly.  
   
   
       15 . The rig of  claim 14  wherein said subsea shutoff assembly includes a pair of shear blowout preventers.  
   
   
       16 . The rig of  claim 15  including a remotely operable latch to disconnect a connector from said subsea shutoff assembly in the event of an emergency.  
   
   
       17 . The rig of  claim 16  wherein said connector is tensioned.  
   
   
       18 . The rig of  claim 17  wherein said subsea shutoff assembly includes a pair of shear ram subsurface blowout preventers and said connector on top of said pair of shear ram subsurface blowout preventers.  
   
   
       19 . The rig of  claim 13  including a riser coupled to said surface blowout preventer.  
   
   
       20 . The rig of  claim 19  including a choke coupled to said surface blowout preventer to control the pressure in said riser.  
   
   
       21 . The rig of  claim 13  wherein said rotating head includes a resilient packer and a drill string and tubing, said resilient packer to seal the region between said drill string and said tubing and to transfer rotational energy from said tubing to said drill string.  
   
   
       22 . A method comprising: 
 operating a subsea wellhead in an underbalanced or balanced condition;    providing mud at a first density to said wellhead; and    injecting, from the sea surface, a first density lowering fluid, into mud returning from said wellhead, through a drill string.    
   
   
       23 . The method of  claim 22  including producing hydrocarbons from a subsea well in an underbalanced condition using a rotating head mounted on a surface blowout preventer.  
   
   
       24 . The method of  claim 23  including using the surface blowout preventer to provide surface flow control.  
   
   
       25 . The method of  claim 24  including providing a subsurface blowout preventer in addition to said surface blowout preventer.  
   
   
       26 . The method of  claim 25  including providing subsurface shear blowout preventers.  
   
   
       27 . The method of  claim 23  including providing a rotating head that transfers rotational energy to said drill string through a packer.  
   
   
       28 . The method of  claim 27  including providing said rotational energy through a resilient packer.  
   
   
       29 . The method of  claim 28  including operating a valve to begin the injection of the first density lowering fluid when production is ready to begin.