mud motor drilling

How a Mud Motor Works

The first machine-like tools ever created, as far as we know, were the bow lathe and the bow drill. Clearly, humanity has been boring holes into the ground for much longer than seems possible. While this was mostly for water wells at one time, most people today who drill into the earth are in search of oil.

A mud (or drilling) motor, for mud motor drilling, is a modern tool used for drilling oil wells. According to Wikipedia, it is a progressive cavity positive displacement pump (PCPD) that is placed in the drill string and provides 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,” the Wikipedia definition continues.

In other words, in mud motor drilling, the mud motor utilizes the force generated by the flow of drilling mud through the drill system, thus increasing a drill bit’s power.

The Torquato Plugbuster is one very powerful, highly effective model of mud motor.

Mud motors use various stator and rotor configurations in order to offer optimum performance, specifically tailored for the mud motor drilling operation being performed. This typically increases the number of lobes and the length of the power assembly, resulting in greater horsepower.

For some applications, compressed air (or some other gas) will be used to provide the mud motor its input power.

Under normal working conditions, the drill bit can be rotated at a speed anywhere between 60 and over 100 RPM while using a mud motor.

The basic principle behind the mud motor is a theory developed by Rene Moineau. Moineau’s theory states that the helical rotor inside the drill bit, with at least one lobe, will spin eccentrically if the attached stator contains a higher quantity of lobes than what the rotor possesses. Then, the flow of fluid from the drill transmits the power necessary for the mud motor to function. This allows the whole assembly to rotate, thus turning the bit.


This article has described in basic detail the origin, construction, and function of a mud motor, for the purposes of mud motor drilling in oil field applications. You should now understand its basic use and application.

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