RECOVERY METHOD FOR OIL-SOURCE CARBONATE RESERVOIRS Russian patent published in 2017 - IPC E21B43/16 E21B43/26 E21B43/27 

FIELD: petroleum industry.

SUBSTANCE: invention refers to the petroleum industry. The method of recovery of oil-source carbonate reservoirs includes drilling, recovery, and extraction of product from wells, and definition of the injection capacity of wells. An oil-source carbonate collector is selected with the average absolute permeability of at least 2 mD. All wells should be production wells with horizontal ends. In the horizontal shafts, the multistage hydraulic fracturing is performed, after completion of a condition in one of the wells q_l < 0.3·q_l⁰ where P_b < 0.3·P_for⁰, where q_l is the current liquid rate of a well, q_l⁰ - is the initial liquid rate after commissioning of a well before corresponding withdrawal/pumping cycle, P_b s the current bottom hole pressure, P_for⁰ is the initial formation pressure, this such well is switched to the pumping of the operation agent with gradual increasing of consumption from 0 to q_pump^max, where q_pump^max is the maximum consumption of a mixture at the pumping pressure of P_pump = (0.5-1.0)·P_rock, where P_rock is the vertical rock pressure. The mixture of acid with the initial concentration of 15-24%, surface-active agents (SAA) with the concentration of 0.2-1.0%, and water with the total mineralization of no more than 1.5 g/l - the rest is used as the operation agent. During the pumping, the acid concentration is gradually reducing to the null. The ratio of these components, such as SAA, acid, and concentration reduction rate, is defined according to laboratory testing for determination of a compound showed the best core oil recovery factor. After achieving q_pump^max the pumping stops, and the well stop either for redistribution of pressure in the reservoir for 10-100 days long, after that, the well may be commissioned into production, the cycles of the pumping and withdrawal are repeated. The same operations should be performed in all wells of the oil-source carbonate reservoir.

EFFECT: technical result lies in the increasing of oil production from oil-source carbonate reservoirs.

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