On solving the problems of maximizing the development of oil reserves in the drainage zone of wells and reservoirs
A new experimental finding regarding the violation of Darcy's law during the flow of liquids in a microcrack with an opening less than its critical value h<hcr, i.e., the manifestation of the "microcrack-fluid" effect is observed, which is the reason for the violation of Darcy's law. It has been revealed that when liquid moves in fractured and low-permeability media with an opening of h<hcr, an additional force arises due to the "microcrack-fluid" effect, which prevents the movement of liquid and this is the reason for the low oil recovery coefficient. The effect in the “microcrack-fluid” system is the reason for changes in the mechanical properties of fluids in microcracks and equivalent ultra-low-permeable porous media. It was revealed that when a one-parameter viscous fluid flows through a crack with an opening h<hcr, it becomes a two-parameter fluid, i.e. it behaves as an anomalous fluid. When the fluid flows through a crack with an opening h≥hcr, it restores one-parameter properties. The anomalous behavior is accompanied by an increase in the rheological constants of the model. Based on the developed methodological guidelines, rheological parameters of filtration systems and crack opening under reservoir conditions are determined. According to the research data, the proposed technique makes it possible to estimate the effective crack opening and the corresponding permeability of the porous medium of the bottomhole zone with sufficient accuracy for practice under steady-state well conditions without interrupting well operation. Therefore, to attract residual oil to the well faces, it is necessary to develop measures that allow deposits to be transferred from the h<hcr state to the h≥hcr state and ensure well flow. Keywords: microcrack opening; Newtonian fluid; structural viscosity; "microcrack- fluid" effect.