METHOD OF DEVELOPING WELL KILLING (VERSIONS) Russian patent published in 2002 - IPC

FIELD: oil recovery; methods of wells preparation for servicing and workover and cleaning of bottom-hole zones, particularly, killing of wells and their cleaning from asphalt-resinous- paraffin deposits. SUBSTANCE: method includes injection of killing fluid and displacing fluid into well annular space with opened tubing at wellhead; displacement of killing fluid to bottom-hole zone with closed tubing at wellhead; injection of displacing fluid from well annular space to tubing with tubing opened at wellhead. Killing fluid is used in the form of oil solution of mixture of chlorinated hydrocarbons left in rectification column still after separation of commercial trichloroethylene and methylene chlorine with solvents. Additionally introduced into said solution is butyl cellosolve. Density of killing fluid exceeds that of displacing fluid. Killing fluid is injected into annular space in volume of well part from pump to bottom hole. According to the other version, method included injection of killing and displacing fluids into well annular space with tubing opened at wellhead; injection of displacing fluid from well annular space into tubing. Killing fluid is used as an oil solution of mixture of chlorinated hydrocarbons left in rectification column still after separation of commercial trichloroethylene and methylene chloride with solvents. Additionally introduced into said oil solution is butyl cellosolve. Density of killing fluid exceeds that of well fluid. Injection of displacing fluid into annular space and tubing is accomplished after settling of killing fluid in bottom-hole zone. Killing fluid is injected into annular space in volume of well part from pump to bottom hole. EFFECT: lower cost and accelerated process of development well killing, higher efficiency of well cleaning from asphalt-resinous-paraffin deposits. 5 cl, 2 tbl