METHOD OF THERMOCHEMICAL CLEANING OF BOTTOM-HOLE ZONE Russian patent published in 2001 - IPC

FIELD: oil producing industry; applicable in development of wells with increase of oil formation permeability due to removal of highly molecular and paraffin-hydrate accumulations from oil. SUBSTANCE: method includes installation of tubing shoe in well in interval of upper perforation holes. Tubing shoe is made in the form of plug from silumin alloy. Internal space of tubing is filled with granulated magnesium. Injected through tubing-casing annulus to bottom-hole formation zone is hydrocarbon solvent together with emulsifier in volume not less than volume of pores of treated colmatage zone and kept in formation for time required for reaction. Then rated volume of 15-% hydrochloric acid is injected to well through tubing-casing annulus. Upon completion of exothermic reaction of hydrochloric acid with granulated magnesium on well bottom, with open casing-wellbore annular space, injected into well is 11-% aqueous sodium bisulfate NaHSO₄H₂O and 5-% solution of sodium carbonate separated in tubing by displacement fluid, and then tube space is opened. As a result of exothermic reaction between magnesium and hydrochloric acid, temperature in wellbore rises by 100 C to ensure heating of well zone complicated with asphalt-resin-paraffin accumulation. Formation of considerable volume of gas in wellbore and their subsequent passage through casing-wellbore annulus and pipe space build up differential pressure exerted on formation to ensure removal from well zone of dissolved organic substances and intensive withdrawal from well of dissolved colmatage formation, spent solutions with increased fluid inflow. EFFECT: increased well production rate. 1 tbl, 1 ex