Abstract: Ansai Oilfield is a typical low-permeability reservoirs,after 20 years of development,it has entered the high water cut stage,the development contradictions are increasingly prominent,which mainly manifest in fast production decline after water production in oil wells,developed natural microfractures,complex remaining oil distribution,casing damage,flooding shut increasing year by year and etc.In combination with development practices of Ansai oilfield,based on the remaining oil distribution regularities,the studies on pattern adjustment,repeated fracturing,water control flooding,controlling measures of casing damage have been carried out and the effective use of technology remaining oil has been developed.The technology has been applied in wells of Ansai oilfield for 1100 times,with accumulative oil production of 20 million tons,increased recovery of 1.8%and good overall development situation.