Rotary Steerable System
The Rotary Steerable System in action (field trial Czech Republic):
Casing has a much higher rotational stiffness when compared to a drill string what results in strongly reduced string twist and stick/slip effects. For most wells, the relation between bit RPM and topdrive RPM becomes direct enough to allow bringing the control system to surface instead of using electronics downhole. The stability of casing drilling enables a unique drilling concept: a by the topdrive continuous controlled system that enables fully automated directional drilling. Standard MWD equipment is used close the control loop and no pressure pulses for down linking is required.
The combination of casing drilling and a point-the-bit Rotary Steerable System results in a low risk drilling system to can drill and install casing in the softest and most unconsolidated formations without problems. All equipment sits inside casing so small stick-out (<1m) and well protected.
The benefits of the Rotary Steerable System:
- Fully mechanical and simpler than mud motor because internals are not exposed to drilling forces: cost effective drilling & low Lost In Hole values.
- Continuous steering for smooth and accurate steering -> excellent for automation.
- Point-the-bit for optimal drilling performance and constant and predictable directional performance regardless formation strength. The system has drilled open hole laterals from vertical.
- Fully rotating to minimize drag and sticking.
- BHA kept well protected within rigid casing to prevent vibrations & wear.
- Very user friendly, minimum experience required to operate