DEVELOPMENT METHOD OF OIL DEPOSITS WITH CHANGEOVER TO FORCED OPERATION CONDITIONS AT FINAL STAGE Russian patent published in 2013 - IPC E21B43/16 

FIELD: oil and gas industry.

SUBSTANCE: development is performed in three stages according to the method. At the first stage, working agent is pumped with increase in several stages of time in 4-12 months. The term is determined depending on duration of positive effect. Increased is performed by 5-30% before initial pressure, but not exceeding hydraulic fracture pressure of that deposit formation. Bottom-hole pressure is maintained at initial level in production wells. Duration of the first stage is determined to a local extremum point of a graph of value of relative efficiency of flushing in time. Then, the second stage is chosen, at which pumping of working agent is performed with reduction in several stages - once in 4-12 months by 5-30%. Production wells with water content of more than 95% are shut off simultaneously. On the rest production wells there reduced is bottom-hole pressure to maintain constant pressure drop between injection and production wells. Bottom-hole pressure in production wells is reduced to gas saturation level; after that, the final stage is chosen. For that purpose, injection wells are shut off, and in production wells there performed is forced liquid takeoff by reducing bottom-hole pressure below saturation pressure by 30-40%. Production wells with water content that is higher than maximum allowable level or well flow rates below economic efficiency are shut off.

EFFECT: reduction of material costs and improvement of oil extraction coefficient due to possibility of action on the whole deposit.

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