Research and Field Application on Extreme Subdivision Water Injection Technology for Low Permeability Reservoirs

Abstract Low permeability Block A is about to enter the development phase of extremely high water cut. Due to the low overall recovery degree and residual oil scattered sporadically, the efficient development meets more difficulty and conventional residual oil analysis and adjustment methods cannot fulfil the current needs of precise development. To enhance the reservoir utilization degree, we conduct extremely concise zonal water injection experiment from three aspects: sand body description, policies establishment, and proper technique application. In terms of sand body description, four types of sand-body distribution patterns were summarized through fine characterization of vertical, planar, and spatial single sand bodies, clarifying the origin and potential distribution of residual oil. In terms of development policy, numerical simulation and reservoir engineering methods have been comprehensively applied to determine the subdivision combination of injection layers and reasonable water allocation boundaries, and subdivision principles have been established, considering single septation to thin and thick layer with combining enhancing -controlling. In terms of supporting technology, we have studied the small space subdivision process of small compartments, optimized the testing and adjustment methods, and finally achieved accurate separation, strict clamping, and accurate matching of water injection layers. Through the research and practice, it realized the finest septation of the water injection to extremely enhance the subdivision degree and the efficiency of the injection. It also have strengthened the utilization of thin and poor layers and effectively controlled the decline.