LOESBARE VERBINDUNG FUER EINE STEIGLEITUNG

摘要

A latching and unlatching system for connecting a riser pipe to the casing in a subsea well. A split-circumferential ring fits into mating grooves in the male end of the casing and the female end of the riser. A releasing tool runs on a drill pipe suspended within the riser pipe and has a number of radially extendible pistons actuated by hydraulic pressure through the drill pipe to expand the split ring out of the casing groove to the grooved recess of the riser pipe. This releases the riser pipe from connection with the casing so it can then be raised.