METHOD FOR TREATING BOTTOM-HOLE ZONE OF WELL Russian patent published in 1998 - IPC

FIELD: oil production industry. SUBSTANCE: this relates to wells which opened oil bed being nonuniform in permeability and saturation. According to method, injected into bottom-hole zone of well are agents which change filtration resistance of bed. Injection of agents is performed under pressure variable in time. Agents which reduce filtration resistance are injected at bottom-hole pressure increasing in time, and agents which increase filtration resistance are injected at pressure reducing in time. Injected into bottom-hole zone of well are successively agent increasing filtration resistance, then agent reducing it. First agent is injected at bottom-hole pressure increasing in time. Second agent is injected on the contrary at bottom-hole pressure reducing in time from maximal value (not exceeding hydraulic breakage pressure) down to bed pressure. Efficiency of treating is achieved due to better selectivity in delivery of agents which reduce filtration resistance into low-permeable layers of bottom-hole zone with substantial residual reserve of oil, and in delivery of agents which increase filtration resistance into high-permeable, crossed by fissures, watered, and gassed layers of bed. EFFECT: high efficiency. 1 tbl