METHOD FOR DEVELOPING AN OIL RESERVOIR IN CARBONATE RESERVOIRS OF BASHKIRIAN STAGE Russian patent published in 2023 - IPC E21B43/20 

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry, in particular to methods for developing hard-to-recover oil reserves in tight non-permeable reservoirs, in particular carbonate reservoirs of Bashkirian stage. A method for developing an oil reservoir in carbonate reservoirs of Bashkirian stage includes drilling a production well to tap an oil-bearing formation and an injection well to tap an oil-bearing formation and underlying aquifers putting the production wells into operation, flooding the oil-bearing formation by pumping in the injection wells from the aquifer to the oil-bearing formation, extracting production from the oil-bearing formation through the production wells. The injection well pumping from aquifers into the oil-bearing reservoir is performed at a constant pressure with alternate operational downtime of the injection well. At the same time, an initial formation pressure P_form is determined and the water-bearing bed in production wells and in the injection well, the oil-bearing bed in production wells, the rock-cover both above the oil-bearing bed and under the water-bearing bed of the production well, the thickness of the rock-cover and the area of its distribution are identified. Production wells with a thickness of at least 2 m and with the area of the whole deposit are drilled with the oil-bearing stratum penetrated by a compacted grid with 100 m or 200 m distance between the wells near the Bashkirian water-bearing stratum and the bedrock above the oil-bearing stratum and below the water-bearing stratum. Production wells are drilled with a diameter of 102 mm. The injection well is drilled and the water-bearing interval is perforated. Reactive production wells are identified after the production wells are put into operation. Then the productive formation is flooded for 180 days with 60-80 m³/day of waste water injection and 1.5*P_form pressure, which does not exceed the maximum allowable pressure on the productive formation. The injection wells are stopped for 180 days period of alternate operational downtime.

EFFECT: invention provides for increase the oil reservoir development method efficiency.

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