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

Unbalanced drilling technology 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 offshore drilling. To ensure safe drilling and protect reservoir, through research and optimization of the unbalanced drilling technology, 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 technology, and the results of the application to offshore oil and gas fields are introduced in this paper. The successful application of the technology indicates the “offshore pressure-controlled drilling technology” can be a new drilling selection for development of offshore oil and gas.