Rotary Steerable Drilling Assembly Torque Control
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Solution Overview
Problem
Current rotary steerable drilling systems (RSS) are complex, expensive, and have limited run times due to battery and electronic limitations, requiring frequent maintenance and large pressure drops for effective operation.
Innovation Solution
A rotary steerable drilling assembly that includes a driveshaft, a bend adjustment assembly, and a torque control assembly with a spool valve and rotary pilot valve to selectively adjust torque transmission and fluid flow, allowing for adjustable deflection angles and operational modes to optimize drilling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a downhole motor is used for directional drilling, then the drill bit can be steered to create deviated boreholes, but longitudinal friction from sliding contact between the stationary drill string and borehole wall hinders motor performance
Solution Approach 1:
The patent transitions from a stationary drill string to a dynamically rotating drill string that rotates at controlled speeds. The rotary steerable system allows the drill string to rotate while maintaining directional control, converting sliding friction into rolling friction and dramatically reducing energy loss along the borehole wall.
Solution Approach 2:
The patent replaces the traditional downhole motor system with a rotary steerable system that uses rotational motion of the drill string itself to achieve directional drilling. This substitution eliminates the need for a separate downhole motor and reduces the mechanical friction problems associated with stationary drill strings.
2Ease of operation
If conventional rotary steerable systems are used, then directional control is achieved, but the systems are complex and expensive with limited run times due to battery and electronic limitations
Solution Approach 1:
The patent extracts and removes the complex battery and electronic control components from the downhole rotary steerable system. By eliminating these limited-run components, the system achieves unlimited operational duration while maintaining directional control capabilities through purely mechanical means.
Solution Approach 2:
The rotary steerable system is designed to be self-contained and self-powered, using the rotational energy already present in the drilling operation. The system requires no external power sources or complex electronic controls, making it self-sufficient and eliminating maintenance requirements.
3Ease of operation
If conventional rotary steerable systems are used, then directional drilling is enabled, but large pressure drops are required for effective operation
Solution Approach 1:
The patent replaces hydraulic actuation systems that require large pressure drops with a mechanically-driven rotary steerable system. The directional control is achieved through mechanical means using the rotational motion of the drill string, eliminating the need for high-pressure fluid actuation.
Data Source
AI summary
A rotary steerable drilling assembly includes a driveshaft rotatably disposed in a driveshaft housing, a bend adjustment assembly coupled to the driveshaft housing, a bearing mandrel coupled to the bend adjustment assembly, and a torque control assembly including a rotor configured to couple with a drill string; a stator assembly coupled to a downhole motor; and a torque control actuator assembly configured to control the amount of torque transmitted between the rotor and the stator assembly, wherein the torque control actuator assembly includes a spool valve including a cylinder including a port and a hydraulically actuatable piston slidably disposed in the cylinder.