METHOD FOR THERMOCHEMICAL TREATMENT OF BOTTOM-HOLE FORMATION ZONE Russian patent published in 1995 - IPC

FIELD: oil producing industry. SUBSTANCE: used instead of injection-of known reagents (powder of aluminum, magnesium) is injection into bottom-hole formation zone of aqueous solution of carbamide for decomposition of which injected, beforehand into formation, is steam or steam-air mixture due to which bottom-hole formation zone is heated up to 150 C and over. Carbamide is decomposed to form ammonia which reacts in formation with hydrochloric acid injected into formation, and liberated, in this reaction, heat additionally heats the rocks of bottom-hole formation zone. Products of carbamide decomposition (ammonia, carbon dioxide) and reaction of hydrochloric acid with ammonia (ammonium chloride) provide for improvement of cleaning of rocks that promotes increase of well production rate and oil recovery factor. EFFECT: improved safety of thermochemical treatment of bottom-hole formation zone - precludes precipitation in wellbore of solid particles of reagent and non- controlled rise of pressure in well during reaction of precipitated particles of reagent with hydrochloric acid, and extended range of reagents used for the purpose. 1 dwg