The ZYL-7000DS(A) double-crawler full-hydraulic directional drilling rig for coal mines has the functions of coaxial output of driving force for casings and drill pipes, automatic casing and drill pipe handling, inclination angle adjustment, and longitudinal and lateral anchoring. It can realize simultaneous drilling and well protection operations. It can achieve three different drilling techniques: simultaneous drilling of drill pipes and casings, drilling with drill pipes while casings remain stationary, and drilling with casings while drill pipes remain stationary. This is especially useful for preventing problems such as hole collapse, severe deformation, and wellbore blockage by drill cuttings that are prone to occur after drilling in soft coal seams and extremely soft coal seams. The double-pipe drilling rig is mainly developed for the drilling and hole protection processes in soft coal seams. After the drilling operation is completed, the drill pipe can be withdrawn first, and the casing can be temporarily left in the hole for protection. Then, a screen pipe is inserted into the middle of the casing, and finally, the casing is withdrawn, leaving the screen pipe in the hole for continuous protection to ensure that the insertion depth and effective diameter of the screen pipe meet the design requirements.

This directional drilling rig is equipped with two independent high-pressure water supply channels. The high-pressure water output in the annular cavity formed between the inside of the casing and the outside of the drill pipe provides the carrying power for the effective discharge of drill cuttings and coal powder, and can effectively prevent the phenomenon of drill cuttings jamming the drill pipe. The high-pressure water output from the center of the drill pipe provides the rotational power for the screw motor and plays a role in flushing, cutting lubrication, and cooling the drill bit, improving the drilling efficiency and service life of the drill bit.