Ways to Improve Waterlooding Efficiency at Super-high Water-cut Stage of Development and Field Applica-tion

As reservoirs enter super-high water-cut stage of development,most of the injection water flow through larger channels,residual oil distribution are scattered and water injection efficiency is very low.Based on fine de-scription of residual oil distribution,well pattern adjust-ment and pulse water injection were performed in Block7in Gudong oilfield to enlarge swept volume,to tap residual oil potential in low permeability zone,to reduce the area of region of bypassed oil and to improve utiliza-tion factor of injection water.Field application was very successful.