The effect of irreversible deformations on the results of hydraulic fracturing

The article examines the impact of reversible and irreversible deformations of rocks on the development of oil fields, including the effectiveness of hydraulic fracturing (FRACKING). Various models of changes in filtration and reservoir properties of rocks under the influence of pressure drop are analyzed, including linear, exponential, and power-law dependences. Special attention is paid to the consideration of elastic, plastic and elastoplastic deformations in hydraulic fracturing modeling, which makes it possible to calculate more accurate forecasts of fracture geometry, expected flow rates of wells and generally assess the effectiveness of impacts on development facilities. Mathematical models of hydraulic fracturing of varying degrees of complexity are considered, from the analytical models of Khristianovich–Geertsma–de Klerk (KGD), Perkins–Kern–Nordgren (PKN) to three-dimensional numerical models of Full3D. A comparative analysis of methods for calculating the flow rate of horizontal wells is carried out, taking into account the anisotropy of permeability and partially irreversible changes in reservoir properties before and after hydraulic fracturing. The necessity of taking into account irreversible changes is demonstrated in order to increase the reliability of well flow rate forecasts and the effectiveness of measures to increase oil recovery.