METHOD FOR REMOVING OF ASPHALT-RESIN-WAX ACCUMULATION Russian patent published in 1996 - IPC

FIELD: oil producing industry, particular, methods for removing of asphalt- resin-wax accumulations in tubing of oil wells. SUBSTANCE: pressure in the tubing-to-casing annulus is equalized with atmospheric one and heat carrier is injected into the annulus. Prior to injection of heat carrier, the annulus is evacuated up to the moment of pressure drop at the wellhead. Simultaneously with pumping out of oil by bottom-hole oil pump, heat carrier is pumped into intermediate vessel with evacuation. Removal of asphalt-resin-wax accumulations is indicative by reduced viscosity, increased temperature and residual pressure in the intermediate vessel. In course of injection of heat carrier, subject to monitoring is pressure at wellhead, and, should it rise above 4 MPa, injection of heat carrier is discontinued, and the whole cycle of operation, including, evacuation, is repeated. EFFECT: higher efficiency. 1 tbl