Application of offshore pressure-controlled drilling technology to Bozhong 28-1 Oil and Gas Field

Unbalanced drilling is a new international drilling technology. It has already been used in several oilfields onshore. But there are a lot of risks to be used in drilling. To ensure safe drilling and protect reservoir, through research and optimization of the unbalanced drilling the offshore pressure-controlled drilling technology is put forward, the focus of which is to realize micro-overbalanced drilling by using unbalanced drilling equipment, lowering drilling fluid density, and adjusting the wellhead casing pressure. The offshore pressure-controlled drilling technology, the example of the application of the and the results of the application to oil and gas fields are introduced in this paper. The successful application of the indicates the offshore pressure-controlled drilling technology can be a new drilling selection for development of oil and gas.