Compared to conventional rotary drilling operations, the use of a downhole motor (also known as mud motor or drilling motor) allows a higher drilling performance. In addition, the drill string rotation can be lowered, whereby the wear on drill string and casing is reduced. In combination with a MWD system (Measurement While Drilling) numerous directional drilling applications are possible.
Downhole motors basically consist of a helical rotor and a rubber coated stator housing. When the drill mud flows through the motor, the cavities between the stator and rotor are filled. The rotor then performs an eccentric rotational motion that is forwarded to the drill bit as drive power.
Downhole motor assembly:
- Top Sub
Downhole motor and drill string are connected by a sub.
- Catch Sub Assembly
This component secures the internal and external components of the drill motor in an event of damage of the housing. This safety feature allows problem-free recovery of all components at any time.
- Power Section
The central element of the drilling motor consists of a rubber coated stator and a hard chrome plated rotor. In the standard version, the complete stator contour is made of special rubber. For high performance applications, equidistant stators are used. By milling the inner contour out of the stator, the layer thickness of the rubber material can be minimized, which increases the pressure drop in the downhole motor.
- Flexible Drive Shaft
The eccentric rotational motion of the rotor is transmitted to the bearing unit via a flexible drive shaft. This component is critical to allow the typical bend in the housing of the downhole motor.
- Adjustable Bend Housing
The bending angle of the downhole motor can be set directly at the well site. This feature makes flexible adaptation to different project requirements possible.
- Bearing Assembly
The bearing unit receives the high load stresses during the drilling operation. Optional external T2A stabilizer ribs are available to ensure an optimal stabilization in the borehole.