Downhole Motor Downhole motor (PDM drill) is a volumetric downhole power drilling tool that uses drilling fluid as power and converts liquid pressure energy into mechanical energy. When the mud pumped by the mud pump flows into the motor through the bypass valve, a certain pressure difference is formed between the inlet and the outlet of the motor, pushing the rotor to rotate about the axis of the stator, and transmitting the speed and torque to the drill through the universal shaft and the transmission shaft To achieve drilling operations. A progressive cavity volumetric hole bottom power machine, referred to as auger drill.The auger drill, which uses mud and clean water as the power medium and is conveyed to the bottom of the hole through the center hole of the drill rod, is essentially an energy conversion device that converts liquid pressure energy into mechanical energy. During drilling, the auger directly drives the core tube and drill bit connected to the transmission shaft at the bottom of the hole to rotate. The entire drill string is only used as a channel for conveying high-pressure working medium and a rod supporting the counter torque of the drill bit. Compared with conventional drilling, screw drilling has many advantages, such as greatly reduced drill pipe wear and high drilling speed.It is the main tool for directional drilling and has played a role in the field of drilling. The auger drill was first used to punch vertical holes, mainly used to drill a variety of directional holes and special engineering holes (such as mine frozen holes). The maximum drilling depth is 9023 meters. At present, the minimum diameter of auger drills in the world is 44.5 mm and the maximum diameter is 304.8 mm. When auger drilling is used for core drilling, a core tube should be added between the drive shaft and the drill bit to take the core