Cyclic regulation of self-induced hydraulic fracturing cracks to improve the flooding efficiency of low-permeability reservoirs

The article is devoted to the topical issue of optimizing flooding in the development of deposits using a reservoir pressure maintenance system. In conditions of low permeability and weak reservoir connectivity, when water is injected into the injection well, when the injection pressure exceeds the pressure of rock rupture, auto-fracturing cracks occur. In order to ensure the maximum coverage factor of the reservoir by flooding during the development of the field, it is necessary to initiate and maintain the optimal fracture geometry of the auto-fracturing. The aim of the work is to analyze the modes of cyclic regulation of injection into the reservoir to maintain the optimal size of man-made cracks during the development of the field. The article presents the results of hydrodynamic modeling of flooding options with varying injection and shutdown times of injection wells, taking into account the geomechanical patterns of the spread of man-made cracks in the formation. Based on the results of the calculations performed, based on the forecast characteristics of displacement and the rate of oil extraction, the optimal modes of cyclic reservoir flooding were determined. The work is of great commercial importance, which is confirmed by the positive effect in the form of additional oil production within the framework of pilot tests of the proposed scheme. Keywords: self-induced hydraulic fracture; low-permeability reservoir; waterflood; water injection system; horizontal well; bottom hole pressure; reservoir pressure; fracture half-length; periodic injection of water.