保径导向扩孔钻头的设计及其工程应用

岩心钻探中，在砾石（漂砾）等破碎地层采用常规三翼扩孔钻头扩孔时，常出现憋车和卡钻现象，且扩孔效率低。为此，设计了具有导向和保径功能的扩孔钻头。新设计的扩孔钻头在宁夏灵武一个综合地质孔进行了应用，扩孔效果良好，平均扩孔效率3.5 m/h，形成的新孔眼与原孔眼同轴度高，孔径规则，下套管顺利，对第四系破碎地层进行了有效分隔，保障了后续取心钻进和物探测井的顺利进行。

Design and field use of the gauge-protected pilot reaming bit

During core drilling, blockage and sticking often occurs when conventional three-wing reaming bits are used for reaming in broken strata such as gravel (boulder), which results in low reaming efficiency. For this purpose, a reaming bit with guiding and gauge protection functions was designed, and was applied in a comprehensive geological hole in Lingwu, Ningxia, with good reaming effect, and the average reaming footage up to 3.5m/h. The reamed hole was highly coaxial with the original hole, and had a regular gauge, leading to smooth casing running. The Quaternary broken formation was effectively separated to ensure smooth performance of subsequent core drilling and geophysical logging.