关键词: 精细, 控压钻井, 窄密度窗口, 自动反馈, 压力控制

Abstract: Pressure-controlled drilling technology, which is a new-type drilling method based on under-balanced drilling, is a focus of new drilling technological development at home in recent years for the purposes to provide an effective way for settlement of drilling bottlenecks, such as “sticking, collapse, leakage and blowout”. There is a variety of pressure-controlled drilling techniques including constant bottom hole pressure drilling, continuous circulation drilling and dual gradient drilling. This paper focuses on pressure-controlled drilling system independently developed by Drilling Engineering Technology Research Institute of CNPC West Drilling Engineering Co. Ltd. on the basis of constant bottom hole pressure drilling. It also elaborates that this system is used for drilling, connection, tripping and dual gradient mud cap pressure control and linkage process. Take Bai-28 Well in Xinjiang Oilfield for an example. This well shows the results achieved by application of the precise pressure-controlled drilling system. The pressure-controlled precision of this system is 0.35MPa, reaching the controlling level of foreign products of the same kind. This paper also puts forward some constructive suggestions on development of pressure-controlled drilling technology, particularly on the technological issues of leakage and blowout.

Key words: precision; pressure-controlled drilling; narrow density window; automatic feedback; pressure-controlled