Double-wall drilling tools include double-wall gas faucets or gas boxes, double-wall active drill rods, double-wall drill rods, double-wall drill collars, gas-water mixers, positive and negative conversion devices and connection joints. The double-wall drilling tool is suitable for both gas lift reverse circulation drilling and air reverse circulation drilling. The gas lift reverse circulation drilling process has high drilling efficiency, long bit life, good well quality, and drilling in complex formations. The drilling is safe and reliable, and can achieve continuous sampling (core) drilling, saving auxiliary time and reducing labor intensity, etc.; the air reverse circulation drilling process has low air consumption, fast rock cutting back speed, strong ability to carry cuttings, and holes The bottom is clean, the drilling efficiency is high, and the drilling stability is good.

The double-wall drill rods are available in conventional and external flat styles. Various specifications are complete, and can be used with various rotary table and power head drills. The outer pipe of the conventional double-wall drill pipe adopts API standard thread connection, the outer pipe of the large-diameter conventional double-wall drill pipe adopts a special buckle connection, the outer pipe of the outer flat double-wall drill pipe adopts a special buckle connection, and the inner pipe adopts the belt Sealed plug-in connection. The drilling tool has a reasonable structure and a reliable seal. It is widely used in water wells, geothermal wells, dry hot rock wells, shale gas wells, coalbed methane wells, mine rescue rescue holes, gas discharge wells, large-diameter engineering construction and large-diameter pile foundation construction. Users require customized non-standard specifications.