Methods of Research for the Development of Spontaneous Growth of Induced Fractures During Flooding in Low Permeability Reservoirs

Abstract

Development of low-permeability reservoirs leads to intensive flooding at high pressure injection. The induced fracture length extends when the injection pressure exceeds the formation fracturing pressure. In a number of cases, the length of induced fracture can reach 1000 m and even more. This results in high water-cut in adjacent producers. Moreover, during sidetracking, repeated fracturing, drilling a new hydraulically fractured directional or horizontal well, etc., a high pressure in the producer and a high water-cut can arise. It can be due to the spontaneous fracturing from neighboring wells as well as from injectors of adjacent elements of field development system. Thus, the number of injectors, which could potentially lead to the high water-cut / the high pressure in the well, is quite large. In order to find such injector, interference tests, dynamic data analysis (correlation of injection rate, production rate, and water-cut) should be carried out as well as data analysis during the steady-state injection tests in the adjacent injectors. The advantages and disadvantages of the methods, as well as the matrix of the step-by-step application of methods are discussed in the paper. Furthermore, the trajectory of spontaneous fracturing is simulated using the geomechanical simulator, which is implemented in the geomechanical module ("RN-KIN"). It can be useful for interference tests when it is necessary to identify the most likely candidate wells for the rating, and find the optimal set of priority active injectors. This helps one to reduce the number of wells in the research program that leads to the reduction of losses in the injection/production. Thus, the proposed approach can significantly reduce the cost and losses in the injection/production during the interference-tests.