勘探深度在1500～3500m范围内的石油或天然气生产孔或勘探孔、地热勘探孔和矿产地质调查孔,若采用传统的钻探方法,其钻孔结构与石油钻孔相等同,钻孔口径偏大,所使用的钻探设备比较庞大笨重,套管和钻杆的重量也大,钻探成本高。近十年来,出现了以较轻便的钻探设备钻进小直径 Oil or gas production holes or exploration holes, geothermal exploration holes and mineral geological investigation holes with an exploration depth within the range of 1,500 to 3,500 m are equivalent to those with oil drilling if the conventional drilling method is adopted, and the borehole diameter is too large , The drilling rig used is bulky, the casing and the drill pipe are heavy, and the drilling costs are high. In the last decade, smaller diameters have been drilled with lighter drilling rigs