Study on Evaluation Method of Water Injection Efficiency in Low-Permeability Reservoir

Low-permeability reservoirs, especially ultralow-permeability usually show a problem of ineffective water injection which leads to low pressure with high injection-production ratio. It is urgent determine the direction and proportion injection, so as guide adjustment development. Based on theory percolation mechanics combined modern well test analysis method, determination method effective ratio was established. This can not only judge injected but also invalid water. applied typical oil reservoirs; evaluation results showed that extremely permeability ultralow exist situation holding around almost 20% Some areas existed channeling; channeling closely related sedimentary microfacies rather than microfractures, accounts are about 45% The simple feasible, provide technical reference for development strategy drive in low-permeability reservoir.