Universal Joint Hybrid Rotary Steerable Drilling System
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Solution Overview
Problem
Current rotary steerable drilling systems face challenges in achieving high building-up rates and maintaining wellbore trajectory stability due to high lateral forces, wear, and fatigue issues, particularly in push-the-bit systems, and difficulties in controlling wellbore orientation.
Innovation Solution
The easy building-up hybrid rotary steerable drilling system employs a front supporting body with a WOB-TOB deflectable transmission joint and a deflection control system that uses a universal joint and elastic stabilizing device to generate a deviation angle by overcoming a small pushing force, allowing for reliable and stable steering with reduced wear and pressure consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If push-the-bit RSS uses large lateral force from driving piston to push drill bit to deviate, then steering capability is achieved, but building-up rate is low and building-up stability is poor
Solution Approach 1:
The patent introduces a universal joint as an intermediary component between the drill string and drill bit. This universal joint acts as a mediator that transmits torque while allowing angular deviation, enabling the drill bit to change direction without requiring large lateral forces from the push-the-bit mechanism. The universal joint absorbs the steering function, allowing the driving piston to apply smaller, more controlled forces while achieving the desired wellbore trajectory.
2Ease of operation
If push-the-bit part rotates with drill bit under high pushing pressure, then steering function is maintained, but wear is serious and service life is low
Solution Approach 1:
The patent segments the steering system into distinct functional components: the universal joint handles torque transmission and angular deviation, while the push-the-bit mechanism (driving piston and piston rod) is responsible for applying controlled lateral forces. This segmentation allows each component to perform its specific function optimally, reducing the wear on the push-the-bit part by eliminating the rotational friction and collision with rocks that would occur if it had to rotate with the drill bit.
Solution Approach 2:
The universal joint serves as an intermediary that absorbs the rotational motion and torque transmission functions, allowing the push-the-bit components to remain relatively stationary or rotate minimally. This mediator component protects the push-the-bit part from the severe wear and collision with rocks that would otherwise occur during rotation under high pushing pressures.
3Reliability
If static bias point-the-bit RSS uses eccentric ring to control drill bit deviation, then stable building-up rate is achieved, but mechanisms are under high-strength alternating stress and prone to fatigue failure
Solution Approach 1:
The universal joint acts as a mediator that absorbs the high-strength alternating stresses and fatigue loads through its universal joint mechanism. This intermediary component protects the eccentric ring and central driving shaft from the full burden of high-strength alternating stresses, reducing their susceptibility to fatigue failure while maintaining the stable building-up rate achieved by point-the-bit mechanisms.
4Ease of operation
If dynamic bias RSS uses independent reverse motor to maintain deflection, then steering control is achieved, but motor power requirements are high
Solution Approach 1:
The universal joint serves as a mechanical intermediary that passively maintains deflection through its inherent ability to accommodate angular deviations while transmitting torque. This mechanical mediation eliminates or reduces the need for high-power reverse motors that would otherwise be required to actively maintain deflection against gravitational and drilling forces, significantly reducing the motor power requirements while preserving steering control capability.
Data Source
AI summary
An easy building-up hybrid rotary steerable drilling system includes a front supporting body, a weight-on-bit (WOB)-torque-on-bit (TOB) deflectable transmission joint and a deflection control system. The WOB-TOB deflectable transmission joint includes a universal joint. A front end of the front supporting body is fixedly connected to a drill bit, and a rear end of the front supporting body is fixedly connected to an outlet end of the universal joint. A front push-the-bit assembly is provided on a circumferential surface of the front supporting body. The deflection control system controls radial push-the-bit parts of the front push-the-bit assembly to push a borehole wall along a radial direction of the front supporting body, such that the front supporting body generates a deviation angle relative to an input shaft of the universal joint by taking a center point of the universal joint as a center, thereby controlling a drilling direction.