Downhole motor is a kind of downhole powered drilling tools with mud as power. When mud pumped out from mud pump flow through the by-pass valve into the motor, pressure difference will be formed at the motor inlet and outlet to make the rotor rotate, and then transmit torque and rotation to drill bit through universal shaft and transmission shaft.
    Downhole motor has a wide range of applications in oil drilling and workover, and is used in drilling operations for geological exploration, coalbed methane, pipeline construction and national defense projects etc.

   Downhole motor is a kind of energy conversion device that converts the hydraulic energy to mechanical energy, and is composed of by-pass valve, anti-dropping device, motor, universal shaft and transmission shaft etc. When the high pressure fluids get into the tool, it forces the rotor to rotate in the stator (rotor and stator compose the motor). The torque and rotation speed generated by the motor are transmitted to the transmission shaft and drill bit through universal shaft, to achieve the purpose of drilling. As the downhole powered device, downhole motor has many advantages of low rotation speed, high torque and large displacement etc. as well as the following:

    1. Increasing the torque and power of drill bits, and improving drilling rate.
    2. Reducing the wear and damage of drill pipe and casing.
    3. Being able to accurately used for orientation, deflection and correction.
    4. Being widely used in vertical wells, horizontal wells, cluster wells and workover operations.