METHOD OF DEVELOPING IRREGULAR MULTIPLE-ZONE OIL DEPOSIT Russian patent published in 1997 - IPC

FIELD: oil and gas production. SUBSTANCE: irregular multiple-zone oil deposit is developed and working agent is pumped in through injecting wells to provide oil production through productive wells. In the late stage of deposit development, at least one well is killed. Preliminarily perforated intervals are cemented and cement bridge is formed in the well to create a new artificial bottom above perforation intervals At the level above upper perforation interval, a new inclined borehole is drilled transforming into horizontal hole in non-exhausted formation or inclined hole passing through several non-exhausted strata. New bottoms are placed at distance no less than 50 m from bottoms of earlier drilled wells. Density of perforations in holes in non- exhausted strata are chosen according to collector properties of strata. Oil is extracted out of all opened strata simultaneously. EFFECT: increased oil production due to fuller coverage of strata and involving earlier not working productive formations.