System and Method for Rescuing a Malfunctioning Subsea Blowout Preventer

Abstract

A pair of rescue vehicles are deployed on deployment cables to force the shear ram of a sub-sea BOP to shut if it should malfunction. The rescue vehicles may be provided with a camera for remote operation from the surface. The rescue vehicles include securing arms to mate with receiving means on the BOP or its enclosure. The securing arms actuate hydraulic means to release the BOP shear ram piston from hydraulic lock. The rescue vehicles carry their own hydraulic fluid under pressure, or hydraulic fluid pressure may be supplied from the surface or from an ROV, in order to actuate a rod which strikes the accessible BOP shear ram tail rod, forcing the shear ram shut. The rescue vehicles also carry their own securing wedges to slide down behind the vehicle rod, securely holding the BOP shear ram shut.

I claim: 
     
         1 . A blowout preventer and rescue system in combination, comprising:
 a. a blowout preventer including a body and at least one pair of rams;   b. a hydraulic system to operate the ram, the hydraulic system including a tail rod accessible from outside the body of the blowout preventer;   c. means associated with the blowout preventer arranged to receive a rescue vehicle; and   d. a rescue vehicle arranged to secure to the receiving means associate with the blowout preventer, the rescue vehicle including means to forcefully contact the tail rod from outside the blowout preventer body, thereby shutting the shear ram.   
     
     
         2 . The system of  claim 1 , wherein the ram is a shear ram. 
     
     
         3 . The system of  claim 2 , wherein the hydraulic system to operate the shear ram including an open line and a shut line, and wherein the system further comprises a control valve in the open and shut lines to controllably disable the hydraulic system. 
     
     
         4 . The system of  claim 1 , wherein the means to receive a rescue vehicle comprises a plurality of horizontally oriented posts arranged on the blowout preventer. 
     
     
         5 . The system of  claim 1 , further comprising a support structure for the blowout preventer, and wherein the means to receive a rescue vehicle comprises a plurality of horizontally oriented posts arranged on the support structure for the blowout preventer. 
     
     
         6 . The system of  claim 1 , wherein the rescue vehicle includes a port securing arm and a starboard securing arm, the arms arranged to secure to the receiving means. 
     
     
         7 . The system of  claim 4 , wherein the rescue vehicle includes a port securing arm and a starboard securing arm, the arms arranged to secure to posts. 
     
     
         8 . The system of  claim 5 , wherein the rescue vehicle includes a port securing arm and a starboard securing arm, the arms arranged to secure to the receiving means. 
     
     
         9 . The system of  claim 3 , further comprising a contactor of the rescue vehicle arranged to contact the control valve in the open and shut lines to controllably disable the hydraulic system. 
     
     
         10 . The system of  claim 1 , further comprising an assist pressure source on the rescue vehicle. 
     
     
         11 . The system of  claim 1 , further comprising a hydraulic coupling on the rescue vehicle to receive hydraulic fluid under pressure from an external source. 
     
     
         12 . The system of  claim 1 , further comprising a deployment cable adapted to couple to the rescue vehicle. 
     
     
         13 . The system of  claim 1 , wherein the means to forcefully contact the tail rod from outside the blowout preventer body includes a hydraulically operated assist rod, and further comprising a locking wedge aboard the rescue vehicle arranged to lock the assist rod when the ram has been operated.