The Study Of Remaining Oil Distribution Law And Water Plugging Technical Policy In Thick Oil Layer At High Water Cut Stage

At present, reservoirs have been developed to increase production and enhance oil recovery is a priority, and to determine the remaining oil distribution is one of the key in oilfield exploitation. Once reservoir is put into development, the original dynamic equilibrium of reservoir was destroyed, fluid distribution are on the complex dynamics of evolution. So the accurate prediction of remaining oil distribution law is very important.In this paper, thick oil layer at high water cut stage in Shengtuo Oilfield is the research object, and visual physical analogy experimental study and numerical simulation study are developed on the basis of making thorough investigation and study on documents about research theory of remaining oil distribution at home and abroad. Remaining oil distribution in thick oil layer include planar seepage law and vertical waterlogged law which are analyzed by combining the results of physical analogy and numerical simulation; The multi-level fuzzy comprehensive evaluation method is used to evaluate the remaining oil distribution and impacting factors; At last the design principles and technical policy of water plugging and tapping the latent power at the high water cut stage in the thick oil reservoir are put forward on the basis of study on the remaining oil distribution law, and the effects of water plugging under different circumstances are also analyzed.The research results show that sedimentary rhythm, permeability ratio, oil viscosity, wettability and the location and distribution situation of interlayer are the important factors impacting remaining oil distribution law; With increasing permeability ratio and oil viscosity the development effect gradually becomes poor and the remaining oil saturation also gradually increases in positive rhythm reservoir. The blocking effect of interlayer make the remaining oil saturation reduce in the upper-layer and rise in the lower-layer,however has little influence on the layer which far away from the interlayer. Reservoir thickness, well pattern and oil recorvery rate etc. have some influence on the remaining oil distribution; Physical simulation results are basically the same as numerical simulation results in reflecting remaining oil distribution law, and it's more comprehensive to combine the two aspects to consider; The discriminant accuracy of multi-level fuzzy comprehensive evaluation is higher in identifying the remaining oil, so it's more practical; General benefit of water plugging is better when plugging radius is 33m and plugging percentage is 100% in the single well obtained from general evaluation of orthogonal design,economic benefits of water plugging and on-site. The research results can provide a basis for tapping the latent power to develop the thick oil layer at the high water cut stage.