Steam injection riser insulation - with insulating material in sealed annulus formed by protective outer tube

摘要

Riser for an injection of superheated steam (350 deg.C) in an oil well is insulated against the casing by a protective pipe. Both ends of this pipe are welded to a lower support ring and an upper end ring. Setscrews are fitted into blind holes of both rings and press a clamp ring with a conical inner face against wedge rings with an outer conical face. The gap between protective pipe and riser is filled with a heat insulating material (calcium silicate). This is an effective way of protecting the heat insulating material against mechanical damage and moisture ingress.