Double Bend Rotary Steerable System for High Dogleg Severity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rotary steerable drilling systems are limited by their maximum dogleg severity, which restricts the maximum deflection rate of the drill string during drilling operations, hindering precise directional control and efficient wellbore placement.
Innovation Solution
The implementation of a double bend rotary steerable system with upper and lower cams and eccentric rings allows for continuous rotation and steering of the drill string, enabling wider ranges of dogleg severity through controlled bending and offset adjustments, facilitated by a control unit communicating with a surface system for real-time directional control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bend configuration is used in the rotary steerable system, then the device complexity is reduced, but the maximum dogleg severity (deflection rate) that can be achieved is limited
Solution Approach 1:
The rotary steerable system is divided into multiple independent bend sections, each with its own cam and eccentric ring mechanism. The first bend and second bend are created at different locations along the drill string, allowing each segment to contribute independently to the overall deflection capability. This segmentation enables the system to achieve higher composite dogleg severities by combining the effects of multiple bends rather than relying on a single bend point.
Solution Approach 2:
The system transitions from a single-dimensional bend (one bend point) to a multi-dimensional configuration by adding a second bend at a different location and orientation. The eccentric rings can be rotated to different angular positions, creating bends in different planes and directions. This dimensional expansion allows the system to achieve a wider range of dogleg severities and steering angles.
2Adaptability or versatility
If multiple cams and eccentric rings are added to increase dogleg severity capability, then the directional control capability is improved, but the device complexity increases
Solution Approach 1:
Each cam and eccentric ring assembly is designed to perform multiple functions: creating the desired bend angle, controlling the bend direction through eccentric ring rotation, and maintaining structural integrity under drilling loads. The control system integrates the actuation of multiple cams and eccentric rings into a unified control architecture that manages all components through a single interface, reducing operational complexity despite the increased number of physical components.
Solution Approach 2:
The system employs dynamically adjustable eccentric ring positions and cam configurations that can be modified in real-time during drilling operations. The eccentric rings can be rotated to different angular positions to change the bend characteristics, and the cams can be actuated to adjust bend angles dynamically. This dynamic capability allows the system to adapt to varying geological conditions and achieve optimal directional control without requiring multiple fixed configurations.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A drilling system may include an outer sleeve, and a rotary steerable module including a shaft extending within the outer sleeve. The rotary steerable module may further include bearings disposed within the outer sleeve and through which the shaft extends, and cams positioned along the shaft between the bearings. Each cam may include an eccentric ring through which the shaft extends. Each extension of the shaft through one of the eccentric rings defines a bend in the shaft within the outer sleeve, the bend having a bend angle. A method of use and a drilling control apparatus are also provided.