Well-riser Repair Collar with Concrete Seal

Abstract

The present invention is a device suitable for capture and containment of oil and gas wells following blowouts or other catastrophic failures, including those in submarine environments, and methods for its construction. The present invention provides a structurally-robust repair collar with integrated locking elements capable of engaging a riser pipe assembly, and an internal structure allowing in situ formation of an impermeable permanent seal through the introduction of liquid concrete into the device. The repair collar can provide means for attaching valves and various other downstream components in order to return pre-blowout functionality to the repaired riser, including oil recovery and flow control capability.

1 . A well-riser repair collar for coupling to a wellhead riser having a wellhead riser flange, the repair collar comprising:
 an outer seal enclosure coupled to an annular cap plate and an inner flow enclosure also coupled to the annular cap plate, the annular cap plate defining an opening adapted to fit over the wellhead riser and whereby the inner flow enclosure and outer seal enclosure and annular cap plate cooperate to define an open-bottomed annular chamber;   the outer seal enclosure further comprising a means for mechanically capturing the riser flange, the means comprising at least one capture pin, which is engaged under pre-load from at least one corresponding hydraulic ram;   the outer seal enclosure further comprising an inlet aperture adapted to direct a material to the open bottomed annular chamber and an outlet aperture adapted to enable other material to escape the open bottomed annular chamber;   and wherein the collar cooperates with the wellhead riser flange to define a three-dimensional area, the collar being located relative to the wellhead riser by the means for mechanically capturing the riser flange.   
     
     
         2 . The collar of  claim 1  further comprising:
 the at least one capture pin comprises a plurality of annularly arranged capture pin. 
 
     
     
         3 . The collar of  claim 1  wherein:
 the open-bottom annular chamber comprises two concentric chambers formed within the confines of the outer enclosure and inner enclosure and annular cap plate working in conjunction with the flange and riser to create an inner flow chamber and an outer seal chamber whereby the flow chamber provides a pathway for oil or gas to flow from the wellhead through the collar. 
 
     
     
         4 . The collar of  claim 1  further comprising:
 an extension skirt coupled to a lower perimeter of the outer enclosure. 
 
     
     
         5 . The collar of  claim 1  further comprising:
 at least one gusset plate coupled to an interior portion of the seal chamber. 
 
     
     
         6 . The at least one gusset plate of  claim 5  further comprising:
 a touchdown stop. 
 
     
     
         7 . The collar of  claim 1  further comprising:
 at least one radially positioned external gusset coupled to the outer enclosure. 
 
     
     
         8 . A well-riser repair collar for coupling to a wellhead riser having a wellhead riser flange, the repair collar comprising:
 an outer seal enclosure coupled to an annular cap plate and an inner flow enclosure also coupled to the annular cap plate, the annular cap plate defining an opening adapted to fit over the wellhead riser and whereby the inner flow enclosure and outer seal enclosure and annular cap plate cooperate to define an open-bottomed annular chamber;   the outer seal enclosure further comprising a means for mechanically capturing the riser flange, the means comprising at least one grappler which is engaged under pre-load from at least one corresponding hydraulic ram;   the outer seal enclosure further comprising an inlet aperture adapted to direct a material to the open bottomed annular chamber and an outlet aperture adapted to enable other material to escape the open bottomed annular chamber;   and wherein the collar cooperates with the wellhead riser flange to define a three-dimensional area, the collar being located relative to the wellhead riser by the means for mechanically capturing the riser flange.   
     
     
         9 . A method of repairing a damaged riser comprising:
 providing a well-riser collar according to  claim 1  or  claim 8 ;   providing concrete to the collar by an inlet aperture provided by the collar;   purging fluids and gasses from the collar by an outlet aperture provided by the collar;   setting the concrete in the collar between the outer and inner enclosures provided by the collar;   retracting at least one capture pin or other grappling device provided by the collar;   positioning the collar over the damaged riser;   extending the at least one capture pin or grappling to position the collar relative to a flange provided by the damaged riser.