HEAT-INSULATION METHOD FOR WELL DRILLED IN PERMAFROST ROCK Russian patent published in 2006 - IPC E21B33/138 C09K8/473 

FIELD: oil production industry, particularly to develop and exploit deposits in permafrost territories.

SUBSTANCE: method involves lowering flow string in well, wherein the flow string is provided with packer and circulation valve; packing and injecting heat-insulation material in hole annuity of the well defined by flow string and casing pipe. The heat insulation material is suspension containing non-freezing liquid having density not exceeding well fluid density and gas-filled microspheres treated with lanoline acids taken in amount of 0.1-0.4% of total gas-filled microsphere mass. The heat insulation material volume is selected to fill hole annuity for depth calculated by equation. Nonfreezing liquid volume, total microsphere mass, hole annuity volume measured from well head to heat-insulation material injection depth and volume of well fluid discharged to well head from hole annuity are determined from formulas. Packing operation is carried out after heat-insulation material displacement with gaseous agent. The gas-filled microspheres are formed of glass or silica-alumina or polymeric material. The gaseous agent is exhaust gas generated by combustion engine or gas from adjacent well line.

EFFECT: increased well heat-insulation efficiency.

3 cl, 1 tbl, 1 ex, 2 dwg