Abstract: Weishen-5 Well in Daqing Oilfield was explored with the under-balanced drilling technology in order to explore the deeper gasproducing zones in Songliao Basin. During drilling process, water-oil drilling fluid was used to avoid the producing zones from contamination. The control technology of under-balanced pressure differential at bottom hole was applied in drilling Weishen-5 Well. A good result has been achieved. The penetration rate was improved, and high-yield industrial gas was discovered. The parameter design, optimization and operation of equipments were introduced. It is suggested that the under-balanced drilling technology can be further tested in drilling engineering of the sandstone reservoir in Daqing oilfield.

Key words: under-balanced drilling technique, deep-seated gas, bottom hole pressure, under-balanced pressure differential, control technology, Daqing Oilfield

摘要： 卫深5井是大庆油田2002年重点探井,钻探目的是评价松辽盆地东南断陷区徐家围子断陷带营城组、沙河子组及火岭石组火山岩及砂砾岩含气情况。在该井采用了欠平衡钻井技术,钻探过程中采用水包油钻井液,选择合理的欠压值和井控技术进行了欠平衡钻迸。有效地解决了该区低渗透火山岩储层在钻探过程中易受污染的问题,保护了储层,及时发现了高产工业气流,提高了深井钻井速度。文中介绍了该井工程参数设计、设备选择和现场试验中久平衡钻井工艺技术研究与应用情况和井底欠压值的控制技术,建议在大庆油田继续开展以砂岩为主的油气藏欠平衡钻井试验研究。

关键词: 欠平衡钻井技术, 深层气, 井底压力, 欠压值, 控制技术, 大庆油田