Abstract: Marginal reserves are important parts of Bohai's reserves. However, limited by the economic and technical limitations of offshore marginal oilfields, it is difficult to develop them. In recent years, Bohai has successfully developed several marginal oilfields in Bozhong region and Caofeidian region by tackling technical problems such as few well slots, small underground oil-bearing area and high drilling and completion investment, etc. Experiences have been accumulated in the development of marginal oilfields. By using extended reach wells, single barrel double wells, wellhead tie back, single well and double pumps and other technical methods, a set of simplified engineering facilities suitable for Bohai marginal oilfields and drilling and completion technologies relying on existing facilities have been formed, and good economic benefits have been achieved. On the basis of relevant technologies at home and abroad, this paper analyzes the bottleneck of drilling and completion technology that restricts the production of marginal reserves in Bohai, sorts out the development ideas of marginal oilfields in Bohai, and thinks about and prospects the future research direction of drilling and completion technology for the development of marginal oilfields in Bohai, which provides a reference for the exploitation of oil and gas resources in marginal oilfields in Bohai.