INJECTION WELL OPERATION METHOD Russian patent published in 2008 - IPC E21B43/00 E21B43/27 

FIELD: oil industry, particularly to operate injection wells.

SUBSTANCE: method involves insulating lower reservoir having high injectivity by installing cement-and-chalk bridge within interval of lower reservoir having high injectivity along with cement-and-chalk mix injection in said interval under pressure within time period enough for partial cement-and-chalk mix penetration in well zone through design depth; performing time-delay for cement-and-chalk mix setting and hardening; operating upper reservoirs after lower reservoir isolation by injecting working agent, namely water, therein. For secondary operation of lower reservoir having high-injectivity acid bath is arranged in well for cement-and-chalk bridge damage. Then new casing pipe having lesser diameter is lowered in well and cement mix is injected in space between old and new casing pipes. After that technological time-delay is carried out for cement mix setting and hardening and both casing pipes are perforated within productive interval reservoir for depth exceeding design depth of partial cement-and-chalk mix penetration into well zone.

EFFECT: possibility to keep producing ability of well.

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