TUBING STRING OF TUBULAR SEGMENTS

摘要

An insert for insulating the area of the coupling two doublewalled tubing segments of an insulated steam injection tubing string. The insert is mounted to overlie both of a pair of adjacent tubing segment end portions radially inwardly thereof. In accordance with one aspect of the invention, the insert has two walls which are spaced apart and connected at their ends to define an annular space therebetween in which thermal insulation may be provided. In accordance with another aspect of the invention, the insert is engaged to one of the end portions and is spaced from the other of the end portions to prevent flowthrough of vapor and to allow vapor to enter between the insert and coupling and condense to provide an insulating medium.