Well-head shock absorber - joining flanges at top of inner casing to sealing socket on outer casing string

摘要

The head for a well with two casings and a riser has a socket which seals the outer against the inner casing string. A set of flanges at the top end of the inner casing is linked to the socket by three shock absorbers, equidistant on a pitch circle. Each of the shock absorbers consists of a cylinder, filled with a hydraulic medium, a piston and a piston rod, with a restrictor in a by-pass. This eliminates dynamic movements by the pumping action in the casing socket. Gentle movements are still possible: the socket wear is much reduced.