Research On Improving The Development Effectiveness Of Water Flooding For Offshore Heavy Oil Reservoir

In the process of water flooding for offshore heavy oil,water/oil mobility ratio is large and swept volume of injected-water is small in size.In addition,the reservoir heterogeneity and interlayer interference is serious,which leads to the lack of water injection in some part of layer and the low crude oil producing extent.Because of the factors above,the recovery of water flooding for offshore heavy oil is low.Aiming at the poor effectiveness of water flooding for offshore heavy oil in A area and the economic and speed demand for offshore oil field,hot-water flooding and separated layer water injection are chosen to improve the effectiveness of water flooding for offshore heavy oil.Laboratory experiment and numerical simulation are chosen as the research methods respectively for hot-water flooding and separated layer water injection.Study influence of hot water temperature on the recovery of heavy oil through indoor experiment.It shows that the recovery of heavy oil rises as the temperature rises,but the trend decreases.Do research on the time that water flooding changes to hot-water flooding.The result indicates that the earlier it changes to hot-water flooding,the higher the recovery will be.Analyze the mechanism of cyclic water flooding recovery and carry out cyclic water flooding experiment.The experiment shows that cyclic water can increase the heavy oil recovery.Evaluate the influence of the time of changing to cyclic water flooding,injection cycle and reservoir heterogeneity on the recovery of cyclic water flooding.The experiment indicates that the recovery is higher when it change to cyclic water flooding earlier,and the best cycle is 1:1,and cyclic water flooding adapts to different reservoir heterogeneities.Entropy weight calculation and cluster analysis are applied to divide the injection layer in area A of offshore oil field and form 3 projects dependent on different numbers of interval.Build geological model according to geologic feature of area A.Conduct numerical simulation and evaluate the different effectiveness between separated zone water injection and the whole interval water injection.Determine the best injection project.