THERMALLY-INSULATED PIPE STRING Russian patent published in 1998 - IPC

FIELD: oil and gas production industry. SUBSTANCE: this can also be used in other industries for thermal insulation of pipelines. Space created between plunger and inner pipe is filled with thermal-insulating material. Rigidly secured is guiding steady rest which is movable in inner tube. After that, inner pipe together with housing-plunger is inserted into outer pipe with flange and sealing unit. Installed on upper end of inner pipe is cap-body carrying preliminarily installed and clamped down sealing device. Cap-body is secured to flange of outer pipe of first section of string. This is done after connecting final section to sinking intermediate section and lower section of thermally-insulated pipe string. This string is rigidly secured by installing it on casing pipe at well head through flange of string outer pipe. Ready thermally-insulated sections are connected together to produce string which is lowered into well in same procedure as applied to pump-and-compressor pipes. In this case, initially coupled are inner pipes of sections, and placed at joint of two sections between guiding steadyrests is thermal-insulating material. Then, after preliminarily lowering of outer pipe, it is connected by means of power-operated pressure nut with tipping coupling sleeve, with nut located on upper part of outer pipe of string, and they are tightly clamped together, so as to seal off coupling joint of string section. EFFECT: higher efficiency. 2 cl, 5 dwg