煤层气水平井充气欠平衡钻井的井底环空压力设计与控制方法

Design and Control of Bottom Annulus Pressure in CBM Horizontal Well Aerated Underbalanced Drilling

井底环空压力的设计与控制是充气欠平衡钻井技术在煤层气水平井中成功应用的关键。在井底环空压力的主要影响因素分析的基础上,提出了一种欠平衡钻进中井底环空压力的设计方法,并探讨了环空压力波动的控制方法。利用该研究成果在彬长矿区2口煤层气多分支水平井进行了现场试验,试验结果表明:该井底环空压力的设计与控制方法是可行的,可在煤层气水平井充气欠平衡钻井中进行推广应用。

The design and control of bottom annulus pressure is the essential of CBM horizontal well aerated underbalanced drilling technology successful application. Based on analysis of bottom annulus pressure main impacting factors, put forward a kind of bottom annulus pressure design method in underbalanced drilling, and discussed annulus pressure fluctuation control method. Using the re？search findings on two CBM multi-branch horizontal wells in the Binxian-Changwu mining area and carried out on site test. The tested result has shown that the design and control method is feasible and can be popularized and applied in CBM horizontal well aerated un？derbalanced drilling.