Studies On Water Injection With Fine Layer Classification In Nan1 Region With Ultrahigh Water Cut

Following the water injection over more than forty years, Nan1 development area has stepped into ultrahigh water cut period, during which the problem between the reserves and production becomes more outstanding, the space for increasing reserve potential turns smaller and the stimulation results are not good as before. So it is required to make fine analysis and fine adjustment in terms of water injection. To most injection wells, it is easy to satisfy the injection rate, but how to realize the maximum production capacity for different layers by water injection is the most crucial.Combining with fine geologic research and advanced well test logging technology, the paper analyzes water out thickness, recovering extent and sub-layer pressure difference among the intervals of various kinds of layers, and conducts the research on the method and criteria for water injection with fine layer classification at the late stage of ultrahigh water cut. With variation coefficient, swept factor and other parameters, the studies on sub-layer amounts within intervals, interval thickness and the relationship between the heterogeneities among the layers and recovering extent have been performed to search for the discipline and to determine reasonable classification principle and the limit of water injection interval, which can optimize the criteria, suitable for water injection with fine layer classification at late ultrahigh water cut, for determining the well and layer selection and interval properties as well. The studies can be used to instruct the adjustment work regarding water injection with fine layer classification at ultrahigh water cut stage, which plays an important role in keeping stable production rate and controlling water cut of water flood.With the numerical simulation, the sandstone model, based on the sub-layer amounts and sandstone thickness, is set up to study the optimal injected intervals, sub-layer amounts and sand thickness within the intervals under a certain condition of well performance, the barriers and the thickness. Considering that the performance of water separate injection is not the same for different layers and the water cut is also different, the next emphasis and direction for water injection with fine layer classification can be determined. And to different regions, the adjustment measures for fine layer injection should be accordingly changed...