LG地区氮气钻井实践与认识

在LG地区高研磨性含气层段的须家河组实施氮气钻井是提高机械钻速，保护油气层，有效避免燃爆事故的发生， 促进该地区勘探开发进程的关键。为此，在多口氮气钻井实践的基础上，总结了在该层段运用氮气钻井时的设备配套、施工技术难点与处理对策：①在钻井过程中要控制钻时钻进（大于5 min/m），防止沉砂卡钻；②出现挂卡严重时，控制上提钻具吨位活动钻具，保持循环，待环空循环通道畅通后再调整钻具活动范围，直至解卡。上三叠统须家河组氮气钻井的成功实施，表明氮气钻井提高了机械钻速，也解决了含气层段空气钻井的燃爆问题。

Practices and experiences from nitrogen drilling in the LG area

The application of nitrogen drilling at the highly abrasive gas-bearing Xujiahe Formation of the LG area is critical for the ROP improvement, reservoir protection, prevention of downhole explosion, and for further exploration and development in this area. Hereby, according to the practices and experiences from the nitrogen drilling in this formation on many wells, we summarized the equipments used, the technical challenges encountered, and the measures adopted as follows: 1) the drilling rate should be controlled to be over 5 min/m in order to avoid sticking; 2) if serious sticking occurs, work the drill string at a controlled pull force, and keep circulating continuously till no obstruction in the annulus, then readjust the work distance of the drill string in order to free it. The successful application of nitrogen drilling at the Xujiahe formation has proved that nitrogen drilling can not only improve the ROP effectively, but avoid downhole fires or explosions when drilling through gas zones with air.