Drill string · Drilling
Mud Motor & RSS
The tools that turn and steer the bit in directional and horizontal wells.
What it does
A mud motor turns the hydraulic power of the drilling fluid into rotation at the bit. With a bent housing it steers while sliding, with the string not rotating. A rotary steerable system steers while the string keeps rotating from surface.
Basics
| Mud motor | Positive displacement, driven by mud flow |
| Steerable motor | Bent housing, steers while sliding |
| RSS | Steers while rotating |
| Used in | Directional, horizontal, extended reach wells |
Common failures
- Slow progress while sliding with a steerable motor
Troubleshooting
- Symptom
- Long sliding intervals slow the well
- Likely cause
- Steering only possible without rotation
- What to check
- Consider a rotary steerable system, which steers while rotating