Definition - What does Mud Motor mean?
A mud motor is a drilling tool located inside the drilling string directly behind the bit. The purpose of the mud motor is to drive the cutting heads of the drill bit through the rock surface. Mud motors use the energy of pressurized fluid to generate the torque necessary for the drilling action.
Trenchlesspedia explains Mud Motor
Mud motors consist of a stator, a rotor, the transmission section and the bearing assembly. The higher the number of stages in the motor, the higher the torque applied to the drill bit will be, but the lower the speed. Mud motors can also be configured with a bend, which enables them to be used for directional drilling. When used with a measurement while drilling (MWD) tool, they can be used by an operator to steer the drill effectively.