1. PRINCIPLE
Downhole motor is a kind of downhole dynamic drilling tool upon the power of drilling mud. Mud stream from the outlet of mud pump flows through a by-pass valve into the motor. This stream produces pressure loss at both inlet and outlet of the pump, to push the rotor into rotating, and to transmit the torque and speed onto the bit. The downhole motor property mainly depends upon its property parameters.
2. ADVANTAGES OF DOWNHOLE MOTOR
Increased rate of penetration.
Better hole deviation control.
Reduction in drill string failure rate.
Reduction in wear and tear of the swivel, Kelly, and rotary drives.
Reduction in fuel cost, since compared to rotary drilling, less energy is required to power a downhole motor.
3. CONSTITUTION
Downhole motor is composed of four assemblies of by-pass valve,motor, cardan shaft and drive shaft