Patent ID: 8256469
Filing Date: 2012-09-04
Classification: E21B,F16L,Y10T

Abstract:
1. A method of draining and venting the permeate gases from a subsea flexible tubular pipe for transporting hydrocarbons, wherein the subsea flexible tubular pipe comprises: at least one internal pressure sheath suitable for transporting the hydrocarbons, whereby permeate gases contained in the hydrocarbons are liable to diffuse through the wall of the internal pressure sheath an external sheath around the internal sheath; and at least one reinforcing ply located in an annular region lying between the external sheath and the internal pressure sheath, the annular region having, along the reinforcing plies, flow paths along which the permeate gases can flow toward a vent proximate to the sea surface for venting the permeate gases; the method comprising: injecting an entrainment gas under pressure at a subsea location near the seabed into the annular region and along the flow paths to force the permeate gases to flow along the flow paths toward the vent; and operating the vent for venting the permeate gases out of the annular region and toward the outside of the subsea flexible tubular pipe.