利用空气钻井技术提高钻井速度研究

采用空气钻井技术提高钻井机械钻速非常有效，钻速是常规钻井机械的数倍。但空气钻井技术较常规钻井技术更为复杂，从装备、井口到钻具组合都有其特点。当地层压力系数小于1时，常规钻井液钻井必然发生井漏，易造成井下工程事故。利用空气充气钻井技术对付地层既出水又发生恶性井漏的井，在川渝地区的钻井作业中，尚属一种全新的工艺技术。通过威寒1井的空气充气钻井实践，解决了因井漏而引起的井下系列复杂问题，大大缩短了复杂井段的钻井作业周期，同时也降低了钻井作业综合成本。

STUDY ON ROP IMPROVEMENT BY AIR DRILLING TECHNOLOGY

Air drilling is one of the effective means to increase drilling ROP, able to reach an ROP several times that of a conventional drilling. However it is more complicated than conventional drilling. It demands special equipment, wellhead, and drilling tools. For formations with pressure coefficient below 1, conventional drilling fluid drilling often leads to lost circulations, causing downhole accidents. Aerated drilling, a wholly new technology, is used in Sichuan and Chongqing area to deal with this kind of complex formations which are both water-producing and subject to serious lost circulations. During the experience on Well Weihan-1, aerated drilling has solved a series of complicated downhole problems caused by lost circulations, largely reduced the drilling cycle of complex well sections, and has reduced the comprehensive drilling costs.