Rotational Anchor Mechanism for Drill String Housing
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Solution Overview
Problem
In directional drilling operations, non-rotating components within drill strings face challenges in maintaining rotational stasis, leading to deviations from the desired well path due to undesired housing roll, which affects the accuracy of directional drilling.
Innovation Solution
A rotational anchor mechanism with a radially expandable anchor linkage and actuating mechanism is mounted on the non-rotating housing, featuring revolute link pairs and a prismatic link pair to resist rotation by engaging with the borehole wall, ensuring the housing remains stationary relative to the drill pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotational anchor mechanism is mounted on the non-rotating housing to resist rotation, then rotational stasis is improved, but device complexity increases
Solution Approach 1:
The rotational anchor mechanism is divided into separate functional components: anchor members for engagement with the borehole wall, anchor linkages for radial expansion and contraction, and actuating mechanisms for control. This segmentation allows each component to be optimized independently while maintaining overall system reliability for rotational stasis.
Solution Approach 2:
The anchor linkage is designed to be radially expandable and contractible, transitioning between retracted and expanded states. This dynamic capability allows the mechanism to adapt to different operational conditions, maintaining reliable rotational anchoring while minimizing interference with the drill string during non-operational phases.
2Force
If the anchor linkage is radially expandable to engage the borehole wall, then torque transfer capability is improved, but device complexity increases
Solution Approach 1:
The anchor linkage employs revolute link pairs and a prismatic link pair that enable radial expansion and contraction through mechanical motion. This dynamic structure allows the mechanism to adjust its radial position, engaging the borehole wall when torque transfer is needed and retracting when not required, thereby enhancing force capability without permanent structural complexity.
Solution Approach 2:
The mechanism changes its radial parameter dynamically through expansion and contraction of the anchor linkage. By varying the radial position of the anchor members, the system optimizes torque transfer capability at different operational stages, transitioning from a retracted state (minimal interference) to an expanded state (maximum torque transfer).
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
The rotational anchor mechanism effectively resists rotation of the housing, maintaining directional control and accuracy during drilling by transferring resistive torque from the borehole wall to the housing, thereby enhancing the precision of directional drilling operations.
Implementation Method 1
transferring rotation-resistive torque from the formation to the housing
Data Source
AI summary
A rotational anchor mechanism is mounted on an operatively nonrotating housing that forms part of a drill string. An anchor linkage forming part of the anchor mechanism is radially extendable and contractible to move an anchor member, such as a roller, mounted on the anchor linkage radially towards and away from the housing, to engage a borehole wall for resisting rotation of the housing relative to drill pipe that is drivingly rotated within the housing. The anchor linkage includes operatively coupled mounting links mounted on the housing to pivot about respective mounting axes which are parallel to one another in a fixed spatial relationship. An actuating mechanism is coupled to the anchor linkage to exert an actuating force on the anchor linkage. An angular orientation of the actuating force relative to the housing varies in response to variation in radial expansion of the anchor linkage.