A mud motor (or drilling motor,downhole motor) is a progressive cavity positive displacement pump (PCPD) placed in the drill string to provide additional power to the bit while drilling. The PCPD pump uses drilling fluid (commonly referred to as drilling mud, or just mud) to create eccentric motion in the power section of the motor which is transferred as concentric power to the drill bit (well). The mud motor uses different rotor and stator configurations to provide optimum performance for the desired drilling operation, typically increasing the number of lobes and length of power assembly for greater horsepower.
Main Features of downhole motor mud motor
1) Increased rate of penetration.
2)Better hole deviation control.
3) Reduction in drill string failure rate.
4)Reduction in wear and tear of the swivel, Kelly, and rotary drives.
5) Reduction in fuel cost, since compared to rotary drilling, less energy is required to power a downhole motor.