Abstract: Measures have been taken to handle the issues of serious flooding in wells of main production layers, complex distribution of residual oil, difficult to explore the potential unconventional oil reserves and limit space of offshore platform in Bohai Chengbei oil field. Based on fine reservoir description, for one thing, the production pressure differential of old well was enlarged to extract fluid by large pump to promote the producing potential of old well with existing equipment; for another thing, adjusting wells were arranged in reservoir edge where well network is imperfect region; High pressure differential was adopted to develop heavy oil in Group Guantao to improve the producing degree of potential reserve on the basis of demonstrating production capacity of unconventional cold heavy oil. The research and application of these methods successfully realize the production replacement in Chengbei oil field; meanwhile provide reference for offshore Oilfields which is entering into the late stage of development.