METHOD FOR DEVELOPMENT OF OIL DEPOSITS IN BAZHENOV FORMATION Russian patent published in 2014 - IPC E21B43/16 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil producing industry. It ensures increase in efficiency of development of oil deposits in Bazhenov formation. The concept of the invention is as follows: according to the method producing and injection wells are drilled and methane-containing gas, associated petroleum gas or natural gas is injected into the formation with observation of a process sequence with alternating cycles and each cycle includes three stages. At the first stage gas is injected into an injection well within T₁ time during which formation pressure is increased, liquid hydrocarbons are dissolved and their bound state in kerogen-containing matrix is released. After T₁ time, at the second stage, the injection and producing wells are withhold within a period of time (T₂-T₁) for further dissolving of the above hydrocarbons and balancing of formation pressure accompanied by further gas penetration to low-permeable kerogen-containing matrix. At the third stage producing wells are put into operation for the period of time (T₃-T₂). Thereafter process of gas pumping is started again to the injection well. Time T₁ is accepted equal to about 1-3 months and duration of the period (T₂-T₁) is set on the basis of field researches on condition of maximizing of accumulated oil production by producing wells by time point T₂. Time point T₃ corresponds to the instant when rate of the oil producing well reaches unprofitable value, for example 3 t/day.

EFFECT: produced dissolved and injected gases after separation are injected back to the formation thus promoting reduction of third-party gas deliveries.

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