Study On Techniques Of Controlling-water And Increasing-oil In Ansai Oilfield With Low&Super Low Permeability In Medium-high Watercut Stage

Matching techniques of controlling water cut and increasing oil production were been studied on Ansai oil field in blocks with a long developing period, such as Wangyao, Xinghe, Houshi. Facing the poor performance of conventional fracturing and acid treatment on those oil wells of low-permeability and super-low-permeability, assessments and optimizations about water-control techniques, including phase-permeability-changed fracturing technology, directional perforation fracturing, water shutoff in bottom-water reservoir and in crack-flooded wells, were investigated theoretically and practically in this paper.The results shows that the fracturing measures can meet the needs of controlling water cut and increasing oil production in oil wells with medium or high water cut in Ansai oil field, while the key to fracturing technique is controlling fracture extension and changing the reservoir wettability. Different water shutoff methods should be conducted in bottom-water reservoir with various types of water breakthrough. Second-cement technique is in good effect with casing damage well in later stage of high water cut. With significant effect of controlling water-cut, the combined technology of directional perforation fracturing to volume-fracturing technique is with great prospect in Ansai oil field.