Embedded multi-string well head shear

Abstract

The present disclosure generally provides apparatus and methods for removing a subsea well head. The apparatus may include an embedded shear comprising a pile and a shear cutter integrated into the pile. The shear cutter may be mounted within the pile near a lower end thereof. The pile may include a well head conductor receptacle adapted to receive a subsea well head, and the shear cutter may include a shear blade that extends across the well head conductor receptacle when activated. The method may include providing a pile with a shear cutter integrated therein, lowering the pile over the well head, pumping water out of the pile to drive the pile into the seafloor to a desired cutting depth, activating the shear cutter to cut off a portion of the well head, and pumping water into the pile to drive the pile out of the seafloor.

1 . An embedded shear comprising:
 a pile; and   a shear cutter integrated into the pile.   
     
     
         2 . The embedded shear of  claim 1  wherein:
 the pile is a suction pile. 
 
     
     
         3 . The embedded shear of  claim 2  wherein:
 the pile further comprises a pump interface. 
 
     
     
         4 . The embedded shear of  claim 1  wherein:
 the shear cutter is hydraulically activated. 
 
     
     
         5 . The embedded shear of  claim 4  wherein:
 the shear cutter further comprises hydraulic cylinders driven by external hydraulic power. 
 
     
     
         6 . The embedded shear of  claim 5  wherein:
 the external hydraulic power is supplied by one of a hydraulic umbilical, an accumulator bottle or a remotely operated vehicle hot stab. 
 
     
     
         7 . The embedded shear of  claim 1  wherein:
 the pile further comprises a well head conductor receptacle adapted to receive a subsea well head. 
 
     
     
         8 . The embedded shear of  claim 7  wherein:
 the shear cutter further comprises a shear blade that extends across the well head conductor receptacle when activated. 
 
     
     
         9 . The embedded shear of  claim 1  wherein:
 the shear cutter is mounted within the pile near a lower end thereof. 
 
     
     
         10 . A method for removing a subsea well head comprising:
 providing a pile with a shear cutter integrated therein;   lowering the pile over the well head;   pumping water out of the pile to drive the pile into the seafloor to a desired cutting depth;   activating the shear cutter to cut off a portion of the well head; and   pumping water into the pile to drive the pile out of the seafloor.   
     
     
         11 . The method of  claim 10  wherein:
 activating the shear cutter comprises providing hydraulic power to hydraulic cylinders to drive a shear blade. 
 
     
     
         12 . The method of  claim 10  further comprising:
 receiving the well head within a well head conductor receptacle of the pile while lowering the pile over the well head. 
 
     
     
         13 . The method of  claim 12  wherein:
 activating the shear cutter comprises driving a shear blade across the well head conductor receptacle to cut off the portion of the well head. 
 
     
     
         14 . The method of  claim 13  further comprising:
 retaining the cut off portion of the well head within the well head conductor receptacle. 
 
     
     
         15 . The method of  claim 14  further comprising:
 raising the pile away from the seafloor while retaining the cut off portion of the well head therein. 
 
     
     
         16 . A method for removing a subsea well head comprising:
 providing a pile with a shear cutter mounted internally near a lower end thereof;   lowering the pile over the well head;   embedding the pile into the seafloor to a desired cutting depth without excavating a glory hole;   activating the shear cutter to cut off a portion of the well head; and   removing the pile from the seafloor.   
     
     
         17 . The method of  claim 16  further comprising:
 raising the pile away from the seafloor while retaining the cut off portion of the well head therein. 
 
     
     
         18 . The method of  claim 16  wherein:
 embedding the pile into the seafloor comprises pumping water out of the pile; and 
 removing the pile from the seafloor comprises pumping water into the pile. 
 
     
     
         19 . The method of  claim 16  further comprising:
 receiving the well head within a well head conductor receptacle of the pile while lowering the pile over the well head. 
 
     
     
         20 . The method of  claim 19  wherein:
 activating the shear cutter comprises driving a shear blade across the well head conductor receptacle to cut off the portion of the well head.