Abstract: Developing a scientific and reasonable drilling and completion technology plan based on the characteristics of low-efficiency wells and remaining oil is the key to achieving efficient reuse of low-efficiency wells. Based on the analysis of the reasons for low production and low-efficiency wells in Bohai Oilfield and the difficulties in tapping the remaining oil in mature oilfields, a targeted drilling and completion technology system has been formed. Conventional lateral drilling technology is used to develop potential sand bodies around old wells for low-efficiency wells with insufficient remaining recoverable reserves. Same layer lateral drilling technology is used to develop well control reserves for sand-production shut-in wells. Four stage completion technology is used to water cone suppression the old wellbore for high water-cut wells. Horizontal multilateral wells are used to achieve development for scattered distribution of remaining oil. Long horizontal sections are used to connect multiple sand bodies for low control reserves in single wells, and small curvature radius drilling technology is used to develop hard-to-produce reserves below the platform. Through the practice of Bohai Oilfield, it has been shown that the above drilling and completion techniques can effectively activate low-efficiency wells, providing reference for the reuse of low-efficiency wells in Bohai Oilfield.