Internal seal for insulated steam injection casing assembly

摘要

An insulated casing assembly for use in injecting steam into wells or transmitting steam from the generating source to the wellhead is disclosed. A plurality of interconnected casings are used, each casing have outer and inner tubular sections and an annular spacing between the two sections containing thermal insulation. Rigid weld rings connect and prevent relative movement between the corresponding ends of the two sections. A thermal and fluid sealing ring disposed between adjacent inner tubular section prevents ingress of steam into the coupling cavity. A threaded coupling screwed onto threaded ends of outer tubular sections joins adjacent casings together.