HEAT-INSULATED PIPE STRING Russian patent published in 1999 - IPC

FIELD: oil production industry. SUBSTANCE: heat-insulated pipe string is used for injecting heat-carrying agent into oil bed. Pipe string has internal pipe which carries multiple-layer screen type insulation, external pipe, and sleeve. Internal pipe is made integral and is provided with beaded profiled ends. External pipe prior to mounting is compressed along axis by 9-12 mm. External pipe has taper-thrust thread on its ends and is provided with valve which is equally distant from pipe ends. After hermetically sealing of seat, valve is made vacuum-tight. Internal and external pipes are made of same material and are welded with vacuum-tight seams at their ends. Arranged on multiple-layer screen type insulation are centering rings, and gas absorber is located between layers of multiple-layer screen type insulation. Created in annular space between pipes is vacuum equal to 10^-4-10^-3 mm Hg. Sleeve is screwed on external pipes. Sealing bush is provided with groove and it presses profiled ends of internal pipe to external pipe. Aforesaid embodiment of heat-insulated pipe string allows for reduction of loss of heat when injecting heat-carrying agent into oil bed together with enhancing performance reliability of heat-insulated pipe string. EFFECT: higher efficiency. 1 dwg