METHOD OF PREVENTION OF WELLHEAD FREEZING OF OIL AND INJECTION WELLS Russian patent published in 2003 - IPC

FIELD: oil producing industry, particularly, methods of prevention of wellhead freezing of oil and injection wells. SUBSTANCE: method includes heat insulation of wellhead and Christmas tree and pressure fittings and use of convective heat source in form of heat transfer from deep layers of ground. Subjected to heat insulation for depth of seasonal freezing are surface casing and external structures of well and well incoming underground pipeline. Use's made of heat- insulating materials with water-repelling shell. For underground part of heat- insulating coating, use is made of heat insulating materials with high mechanical strength, or external protective boxes, for instance, of polyethylene pipes or other strong corrosion-resistant materials. Christmas tree or pressure fittings and well incoming underground pipeline are connected so that branch pipe on well incoming pipeline is higher than branch pipe on fittings by, at least, one diameter of pipeline interconnecting them. EFFECT: increased term of well faultless operation during shutdowns of oil production or water supply, or deficiency in electric power supply in winter time. 1 dwg