Anisotropic Shear Bolt for Downhole Tool Release
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Solution Overview
Problem
Current shear mechanisms used in downhole operations limit the magnitude of forces that can be applied to the drill string, making it difficult to overcome obstacles such as debris or bridges when drilling secondary boreholes.
Innovation Solution
A release device with a shear member having a first shear axis aligned with the longitudinal axis of the string and a second shear axis aligned with the circumferential axis, allowing for higher forces to be applied along the longitudinal axis while maintaining lower resistance for rotation and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional shear mechanism is used to couple the downhole tool to the drill string, then the release mechanism is simple and reliable, but the magnitude of forces that can be applied to the drill string is limited
Solution Approach 1:
The shear member is segmented into multiple shear planes (first shear plane and second shear plane) with different shear resistances. This segmentation allows the mechanism to handle different force magnitudes along the drill string while maintaining structural integrity, resolving the contradiction between force capacity and structural simplicity.
Solution Approach 2:
Different regions of the shear member are designed with different shear resistances - the first shear plane has higher shear resistance while the second shear plane has lower shear resistance. This local differentiation enables the mechanism to apply higher forces along the drill string without compromising the release function, addressing the force limitation issue.
2Force
If the shear resistance is increased to handle higher forces, then the force capacity improves, but the rotational force required for separation increases
Solution Approach 1:
The shear member is divided into multiple shear planes with different orientations and resistance levels. The first shear plane resists longitudinal forces with high shear resistance, while the second shear plane is designed to fail at lower rotational forces, enabling separation without requiring excessive rotational power.
Solution Approach 2:
The shear member exhibits asymmetric shear resistance properties - high resistance along the longitudinal axis and low resistance along the circumferential axis. This asymmetry allows the mechanism to withstand high axial forces during drilling while requiring minimal rotational force for release, resolving the contradiction between force capacity and separation power.
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
This solution enables the application of higher forces along the drill string without limiting the rotational force required for separating the downhole tool, thereby improving the ability to drill through challenging formations.
Implementation Method 1
a shear member therein having a first shear axis that has a first shear resistance and a second shear axis having a second shear resistance
Implementation Method 2
a shear member therein having a first shear axis that has a first shear resistance and a second shear axis having a second shear resistance less than the first shear resistance
Data Source
AI summary
A downhole system and a method of performing an operation downhole. The downhole system includes a string, a downhole tool, and a release device. A downhole tool is coupled to a string via the release device. The release device includes a shear member therein having a first shear axis that has a first shear resistance and a second shear axis having a second shear resistance less than the first shear resistance, wherein the first shear axis is aligned with a longitudinal axis of the string and the second shear axis is aligned with a circumferential axis of the string. The string is conveyed through a borehole to place the downhole tool at a selected location of the borehole. The downhole tool is secured within the borehole and the string is rotated to release the release device.