Riser pipe for pivotally attached structure used to extract petroleum from beneath a body of water

摘要

A riser pipe consists of a plurality of sections of production pipe which are centered and free to slide axially in a guide shaft. The guide shaft is fixed to a pivoted structure and the riser pipe comprises a lower section which is connected at one end to piping at the bottom of the water by means of a remotely controlled releasable connector and at the other end to the penultimate section of the pipe by a connector which is longitudinally slidable to the said guide shaft. The bending stresses on the pipe may be distributed over the length of a lowermost section which may be removed and replaced from the surface.