There are lots of marginal oilfields with small reserves, complex geological conditions and short economic exploitation periods in Bohai. It is difficult to develop effectively under conventional development mode and technology. The key to the development of marginal oilfields is economy. In order to avoid the risk in the overall development of oilfield, we need reduce investment, increase the rate of return and use the “bee” mining mode. In order to satisfy the needs of the overall development of the oilfield, an asymmetric threehole underwater baseplate is designed and made. Combined with the mud line hanger, temporary abandonment of the well after the extension of the test well test is achieved, and the production will be put back in the whole development stage of the oilfield. It provides a new mode of reducing cost and increasing efficiency for Bohai ' s subsequent marginal oilfield development, which will bring huge economic and social benefits, revitalizing a large number of marginal oilfields yet to be developed.