The use of mud motors evolved from vertical drilling in oil patches as drillers were forced to punch through bedrock. Adapting these tools into effective horizontal directional drilling (HDD) equipment required small tweaks to improve functioning, but the basic principles remain the same. Many HDD drillers know a mud motor is a tool for drilling through solid rock, but they may not know much else. This article will outline the specifics of what a mud motor is, how it works, and how these specialized HDD tools can increase efficiency and profitability.


When drilling in a straight line using a mud motor, every piece of the tool rotates. But when the operator wants to change directions, the mud motor’s design enables him or her to stop the drill stem, halting the mud motor’s spin. This results in the independent rotation of only the very end of the mud motor, where the bit is connected. The power section of a mud motor consists of a rotor and stator. These two components harness the pressure and flow of the drilling fluid and translate it into torque and rpm that spins the drill bit. Thus, a mud motor provides simultaneous rotary cutting action and steering.


  • Motors from 3-1/6 to 8-1/2 are in stock and available for rent or purchase
  • High performance mud motor designed specifically for HDD
  • Can be operated at a slower speed that is more compatible with tri-cone bits
  • High torque to flow ratio means you get more drilling power with less fluid
  • High quality internal parts results in more drilling time before regular maintenance is required
  • Rebuild costs are factored into rental rate

Unless drilling in solid rock all the time, renting a mud motor is likely the best course of action. Because mud motors are subjected to such stress, these versatile HDD tools have a wear life. They require basic service after 150 hours of use and a more detailed service after every 1,000 drill hours. Most operations send their mud motors out for repair rather than investing in the specialized equipment required to address maintenance in-house.

Mud Motors allow for a more effective drilling experience…