METHOD FOR SELECTIVE ISOLATION OF WATERED INTERVALS OF OIL BED Russian patent published in 1997 - IPC

FIELD: oil production industry. SUBSTANCE: according to method, increase efficiency in isolation of water inflow to oil bed is achieved by successive injection into producing well of high-viscous oil and concentrated sulfuric acid. Volumetric ratio of acid and oil is taken within 3:5 to 1:1. High-viscous oil will selectively get into high-permeable watered interlayers. At interaction of concentrated sulfuric acid and high-viscous oil, produced is dark, viscous, resinous mass. Thus, created in down-hole zone of watered interval of oil bed is isolating screen which is made up of aforesaid viscous mass. Subsequent initiation of well operation leads to reduced water penetration and increased oil output. EFFECT: high efficiency. 1 tbl