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Downhole Motors 

Sealed oil-filled bearing assemblies of Wenzel M6 Millenium downhole motors are specifically designed to work in extremely difficult drilling conditions and to withstand ultra-high torque power sections. Currently, downhole motors are available in sizes ranging from 241 mm to 79 mm. Some bearings are designed for high axial loads on the bit during drilling and reaming operations. Our downhole motor fleet features special motors with a shorter bearing section (HB-21). The peculiarity of this tool is the distance from the end of the output mandrel to the bent sub, which is only 800 mm, whereas M6 Millenium standard bearing assemblies have a length of 1,725 mm. This allows almost to double the intensity of angle build-up and to reduce the number of RIH/POOH operations to change the steering angle, and permits the simultaneous increase of the rotational speed of the rotor with no risk of damage to the motor.

By the principle of operation, downhole motors are positive-displacement machines with multiple-thread working bodies in the form of a planetary and rotary mechanism with helical gearing. The function of downhole motor is to drill wells under different geological conditions. The benefits of their use include the following:

  • Increased reliability of downhole motors in combination with advanced drill bits and telemetry systems to measure the trajectory during drilling, which enhances the directional drilling for operating companies in addition to the rotary method;
  • Effective downhole motor that corresponds to the type of the drill bit and the rocks, which provides for a higher penetration rate than that achieved by the conventional rotary-drilling method;
  • The motor allows reduction of the drill string rotation speed and decreases the wear of casing and drill strings and other drill string moving parts of the BHA;
  • A correctly selected BHA configuration also enables wellbore drilling trajectory effective control;
  • A power section, which provides drill bit wide range rotational speeds and the effective torque;
  • Latest developments in the area of elastomers and modern production technologies allows using the power section at high downhole temperatures and using invert drilling muds;
  • Adjustable bent sub or fixed bent sub and drive shaft are located between the power section and the bearing assembly and are designed to work at high torque values;
  • In case of complications of drilling programs and increasing the depth of wells, Wenzel Downhole Tools creates bearing assemblies, which can withstand higher load and torque values, while featuring improved reliability and durability;
  • Wenzel Downhole Tools offers bearing assemblies that are lubricated with grease (sealed) or with the drilling mud (open).


  • 241 mm
  • 203 mm
  • 165 mm (171 mm)
  • 121 mm
  • 79 mm

Power sections have different configurations, and fully lubricated bearing sections provide for high torques, a smooth start and operation of motors under various geological and technical conditions and at different angles of the well.

Downhole Motors with Short Bearing Section

  • 165 mm

Short bearing section provides for a high build-up rate and an increase well penetration rate by allowing drill string rotation by the rotor in a wider range of speeds.