METHOD FOR ASPHALT-TAR-PARAFFIN DEPOSITS PREVENTION IN OIL PRODUCTION EQUIPMENT Russian patent published in 2007 - IPC E21B37/00 

FIELD: oil production, particularly methods or apparatus for cleaning boreholes or wells.

SUBSTANCE: method involves lowering production strings with protective coatings preliminarily applied thereto in wells; creating protective coatings in flow lines extending from well. Two part production strings previously covered with heat-protective substance from inner and outer sides thereof are lowered in well. The protective substance includes hollow microspheres. Production string with 5-15 dried or hardened heat-protective layers is lowered under dynamic level of liquid in well. Production string with 2-3 heat-protective layers is lowered over dynamic level of liquid in well. Produced liquid temperature is maintained at level of not less than paraffin melting temperature through interval extending to at least production string top, accessible for asphalt-tar-paraffin deposit removal by thermal methods with the use of heat-carrying agent by increasing number of layers and total heat-protective coating thickness. As asphalt-tar-paraffin deposit layer grows the deposits are removed by thermal and/or chemical methods with the use of processing liquid.

EFFECT: increased efficiency of asphalt-tar-paraffin deposits prevention due to decreased produced oil cooling and provision of guaranteed asphalt-tar-paraffin deposits removal by heat and/or chemical methods with the use of thermal and/or chemical agent, extended field of protective coating usage.

2 cl, 4 dwg, 2 ex