EQUIPMENT FOR PREVENTION OF WARMING-UP OF PERMAFROST ROCKS IN WELL OPERATION Russian patent published in 1995 - IPC

FIELD: oil producing industry. SUBSTANCE: equipment for prevention of warming-up of permafrost rocks in well operation has ejector made in form of diffuser, mixing chamber and converging tube. Equipment has air supply control unit with check valves. Control unit is made in form of external and internal bushings concentrically installed for mutual axial motion. Each bushing is connected with its one end to tubing string. Bushings are made with radial channels whose total flow area may vary during mutual axial motion of bushings. Check valves are located in radial channels of internal bushing. Tubing-to-borehole annulus above packer and mixing chamber of ejector are intercommunicated by means of bushing radial channels. EFFECT: higher efficiency. 2 dwg