Method for assembling and disassembling marine riser and auxiliary lines and well pressure control system

Abstract

A method for assembling a riser from a platform on the surface of a body of water includes assembling segments of riser end to end through a drill floor using a main drilling unit on the platform. At least one auxiliary line is assembled from segments connected end to end through an auxiliary hoisting unit on the platform. The auxiliary hoisting unit is displaced laterally from the main drilling unit. The assembled riser is connected to a wellhead proximate the bottom of the body of water.

What is claimed is: 
     
         1 . A method for assembling a riser from a platform on the surface of a body of water, comprising:
 assembling segments of riser end to end through a drill floor using a main drilling unit on the platform;   assembling at least one auxiliary line from segments connected end to end through an auxiliary hoisting unit on the platform, the auxiliary hoisting unit displaced laterally from a well center of the main drilling unit; and   connecting the assembled riser to a wellhead proximate the bottom of the body of water.   
     
     
         2 . The method of  claim 1  further comprising assembling a lower marine riser package and blowout preventer to a lower end of the riser at the beginning of assembling the segments of riser. 
     
     
         3 . The method of  claim 1  further comprising connecting an accumulator assembly to a lower end of the at least one auxiliary line at the beginning of assembling the at least one auxiliary line. 
     
     
         4 . The method of  claim 3  further comprising connecting the at least one fluid line from the accumulator assembly to a blowout preventer disposed at the bottom of the riser. 
     
     
         5 . The method of  claim 1  wherein the at least one auxiliary line is assembled by threaded coupling of the segments thereof end to end. 
     
     
         6 . The method of  claim 4  wherein the at least one auxiliary line comprises drill pipe. 
     
     
         7 . The method of  claim 1  wherein the riser is assembled by coupling connectors at each longitudinal end of each segment of the riser to a corresponding connector at each longitudinal end of an adjacent segment of the riser. 
     
     
         8 . The method of  claim 7  wherein the connectors comprise bolt flanges. 
     
     
         9 . The method of  claim 1  wherein at least one of the riser segments has a buoyancy device coupled on an exterior thereof during assembly to the riser. 
     
     
         10 . A well pressure control system, comprising:
 a riser coupled at one end to an upper end of a lower marine riser package and blowout preventer assembly, a lower end of the lower marine riser package and blowout preventer assembly coupled to a wellhead disposed on top of a well, the riser extending to a platform on the surface of a body of water;   at least one auxiliary line extending from proximate the bottom of the body of water to the platform, the at least one auxiliary line disposed at a selected lateral distance from the riser; and   at least one fluid line hydraulically connected to a lower end of the at least one auxiliary line and connected to a part of the lower marine riser package and blowout preventer assembly.   
     
     
         11 . The system of  claim 10  further comprising an accumulator assembly coupled to a lower end of the at least one auxiliary line. 
     
     
         12 . The system of  claim 11  wherein the at least one fluid line comprises an hydraulic fluid line extending between the accumulator assembly and the lower marine riser package and blowout preventer assembly, the at least one fluid line selectively conducting hydraulic fluid under pressure to a blowout preventer part of the lower marine riser package and blowout preventer assembly. 
     
     
         13 . The system of  claim 11  wherein the at least one fluid line comprises one of a choke line, a kill line and a boost line, wherein the at least one fluid line is in fluid communication with the well below the lower marine riser package and blowout preventer assembly. 
     
     
         14 . The system of  claim 10  wherein the at least one auxiliary line comprises segments of pipe threadedly coupled end to end. 
     
     
         15 . The system of  claim 10  further comprising at least one buoyancy device coupled to the at least one auxiliary line. 
     
     
         16 . The system of  claim 10  wherein the riser comprises segments of pipe coupled end to end. 
     
     
         17 . The system of  claim 15  wherein the segments of pipe are coupled end to end by a connector disposed at each longitudinal end of each pipe segment. 
     
     
         18 . The system of  claim 17  wherein each connector comprises a bolt flange.