High temperature insulated casing

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 either multilayered thermal insulation or glass microspheres, enveloped in a low conductivity gas. Rigid thrust rings connect and prevent relative movement between the corresponding ends of the two sections. A pressure sealing ring disposed between adjacent inner tubular sections prevents ingress of steam into the coupling cavity. An insulation assembly between adjacent casings includes coupling cavity insulation fitted tightly over the thrust rings and a gap insulating ring disposed between adjacent outer tubular sections. A threaded coupling screwed onto threaded ends of outer tubular sections of adjacent casings joins them.