[Application scope] It is used for the expansion of the local hole section of the drill hole, the expansion of the gas drainage radius of the local hole section (coal bed section) of the drill hole, and the operation of the hole drilling at the bottom of the CBM docking well.
[Technical features] Relying on the hydraulic structure to locally expand the hole in the deep hole to complete the large-diameter digging operation, the bit configuration is reasonable, and it can meet the high efficiency of the rock section and the rapid and efficient operation of the coal layer section.