Rotary Steerable Tool Engagement Member Steering
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Solution Overview
Problem
In directional drilling, existing rotary steerable tools face challenges in consistently steering the drill bit to achieve the desired horizontal well trajectory and correcting drilling angles while rotating, as they struggle to maintain directional control and induce bends in the drill string effectively.
Innovation Solution
A rotary steerable tool design featuring an outer housing with an engagement member that moves axially between extended and retracted positions, utilizing a friction surface with sharp points to engage the wellbore, and an actuator system, such as electric or hydraulic motors, to induce a bend in the drill string, allowing independent rotation of the outer housing and precise directional control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the drill bit is driven by a rotating body, then drilling operation can be performed, but the tool cannot maintain directional control and steering accuracy
Solution Approach 1:
The tool is divided into separate functional components: an inner mandrel for rotation, an outer housing for steering, and an engagement member for directional control. This segmentation allows each component to perform its specific function independently, enabling directional control while maintaining drilling capability.
Solution Approach 2:
The engagement member is designed to move dynamically between extended and retracted positions along the longitudinal axis. When extended, it engages the wellbore wall to provide directional control; when retracted, it allows free rotation. This dynamic positioning enables the tool to adapt between steering and drilling modes.
2Ease of operation
If the engagement member is extended to engage the wellbore wall, then directional control is achieved, but the tool cannot rotate freely
Solution Approach 1:
The engagement member transitions between extended and retracted states based on operational needs. During directional steering, it extends to engage the wellbore wall; during drilling operations, it retracts to allow free rotation. This dynamic state change enables the system to switch between directional control and drilling efficiency modes.
Solution Approach 2:
By separating the rotation function (inner mandrel) from the steering function (outer housing with engagement member), the system can independently optimize each function. The inner mandrel rotates freely for drilling, while the outer housing provides directional control when needed, resolving the conflict between rotation freedom and directional control.
3Measurement precision
If the outer housing rotates independently, then steering accuracy is improved, but the structural stability is reduced
Solution Approach 1:
The tool structure is segmented into an inner mandrel and outer housing that can rotate independently. The inner mandrel handles rotation for drilling, while the outer housing provides steering accuracy through independent rotation controlled by the engagement member. This segmentation allows each component to optimize its rotational behavior for its specific function.
Solution Approach 2:
The engagement member acts as an intermediary between the outer housing and the wellbore wall. It transfers the steering force from the outer housing to the wellbore wall, enabling precise steering control while maintaining structural integrity. The engagement member mediates the interaction between the rotating outer housing and the stationary wellbore wall.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and controlled directional drilling by creating a bend in the drill string, allowing for precise angle corrections and maintaining directional control, enhancing the efficiency and accuracy of well trajectory management.
Implementation Method 1
The friction surface engages the inner surface of the wellbore to prevent rotation of the outer housing as the drill string rotates
Data Source
AI summary
A rotary steerable tool has an inner mandrel having a longitudinal axis and an outer housing positioned along the inner mandrel. The outer housing rotates independently of the inner mandrel. The outer housing has an engagement member that moves axially relative to the outer housing and the inner mandrel between an extended position and a retracted position, and a transition surface having a slope relative to an outer surface of the outer housing. The engagement member moves along the transition surface between the extended position and the retracted position. In the engaged position, the engagement member extends outward from the outer housing to engage an inner surface of a well being drilled. An actuator selectively moves the engagement member along the transition surface from the retracted position to the extended position.