The actuality of increasing the oil (ORF), gas (GRF), condensate (CRF) recovery factors of liquid and gaseous hydrocarbon field, developed through artificial methods of reservoir pressure maintenance, involving the injection of water or other displacing agents, does not depart from the scientific and technical agenda for the oil and gas industry.
The solution of direct problems of filtration of multiphase fluids through an inhomogeneous porous medium by analytical or numerical methods is faced with the problem of taking into account the instability of the displacement front and, as a result, due to a jump in determining water saturation and parameters that depends on water saturation. The proposed solution to the inverse problem allows implicitly taking into account the instability of the displacement front and predicts the consequences of a natural intermittent change in water saturation and dependent parameters using a discriminant analysis of the growth model. On the basis of the proposed solutions, criteria are formulated that enable timely detection of the consequences of loss of the displacement front stability and targeted adjustment of the waterflood system by forcing or limiting the operating modes of production and injection wells in accordance with established discriminant analysis criteria. The mobilization of the injected water and the regulation of the selection of liquid, more precisely, water and oil, based on the discriminant criterion, allow solving an important practical problem in circumventing difficult to solve direct deterministic problems and methods for solving them. This opens up the possibility of systemic optimization of non-stationary waterflooding and the prospect of enhanced oil recovery from field and the intensification of hydrocarbon production.
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