Well drilling and production using a surface blowout preventer
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 drilling rig comprising:
a rotating head;
a drill string coupled to said rotating head and rotated by said rotating head, said drill string including a drill bit, wherein said rotating head includes a resilient packer and said 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;
a surface blowout preventer mounted under said rotating head on said rig;
an apparatus to pump lower density drilling mud to the bottom of a hole through said drill string and drill bit;
a subsea shutoff assembly, said string passing through said assembly, an annulus in said assembly, returning drilling mud to move upwardly through said annulus in said assembly around said string; and
a valve connected to said annulus to selectively inject density lowering fluid into said returning mud.
2. The rig of claim 1 including a connector coupled from said surface blowout preventer to the subsea shutoff assembly.
3. The rig of claim 2 wherein said subsea shutoff assembly includes a pair of shear blowout preventers.
4. The rig of claim 3 including a remotely operable latch to disconnect said connector from said subsea shutoff assembly in the event of an emergency.
5. The rig of claim 4 wherein said connector is tensioned.
6. The rig of claim 5 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.
7. The rig of claim 1 including a riser coupled to said surface blowout preventer.
8. The rig of claim 7 including a choke coupled to said surface blowout preventer to control the pressure in said riser.