Fine water injection for complex reservoirs with bottom water in high water cut stage of Bohai Q oilfield

The western area of Bohai Q oilfield is a typical heavy oil reservoir with bottom water meandering river sedimentary, which is in high water cut development stage. In order to improve water injection efficiency of bottom water reservoir in high water-cut period, in view of the development characteristics of local interlayer in the block, the injection-production well pattern is abstracted into three modes: no interlayer, semi-closed interlayer and closed interlayer. The optimal water injection pattern and injection-production ratio under three patterns are studied by means of reservoir numerical simulation and orthogonal design. The research results show that the stratified water injection based on the distribution of interlayer can not only maintain the formation pressure, but also play a good role in oil displacement. After the research results were applied to the western area of Bohai Q oilfield, the reservoir formation pressure increased steadily and the natural decline rate decreased obviously, the injection-production well group with separated injection has realized oil increase, and the development effect is improved.