Strain Magnification Patch for Downhole Tool Measurement
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Solution Overview
Problem
Downhole tools in the oil and gas industry face challenges in obtaining high-resolution strain measurements due to their robust nature and the magnification of noise in electric strain measurements, which reduces their usefulness in extreme environments.
Innovation Solution
A strain magnification patch is introduced, comprising a stiff section and a weak section with a strain gauge, where the weak section is more deformable and often made from a material with a lower Young's Modulus than the stiff section, allowing for increased deformation and higher resolution strain measurements without introducing weakness into the tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If downhole tools are designed to be robust for extreme environments, then reliability is improved, but measurement precision deteriorates
Solution Approach 1:
The patch is segmented into a stiff section and a weak section, where the weak section has reduced thickness and/or width to provide localized deformability. This segmentation allows the majority of the tool to remain robust while a specific region enables enhanced strain measurement through increased deformation under the same load.
Solution Approach 2:
The patch implements local quality by having different structural properties in different sections: the stiff section maintains structural integrity and connection to the tool, while the weak section provides localized compliance and amplified deformation. This local variation in stiffness allows the measurement region to be more sensitive without compromising the overall tool robustness.
2Measurement precision
If electrical magnification is used to amplify strain measurements, then measurement sensitivity is improved, but noise is magnified
Solution Approach 1:
The patent replaces electrical magnification with a mechanical magnification system. Instead of using electrical signals and amplifiers that introduce noise, the system uses a mechanically compliant weak section that passively amplifies strain through its deformable structure. The strain gauge directly measures this mechanically amplified deformation without requiring electrical amplification, thereby avoiding noise magnification.
3Measurement precision
If the patch material has lower Young's Modulus to increase deformability, then strain magnification is improved, but structural strength deteriorates
Solution Approach 1:
The patch is divided into stiff and weak sections with different thicknesses and/or widths. The weak section uses lower Young's Modulus material or reduced dimensions to achieve higher deformability and strain magnification, while the stiff section maintains structural strength and proper load transfer to the tool. This segmentation allows each section to be optimized for its specific function without compromising overall performance.
Solution Approach 2:
Different material properties are assigned to different sections of the patch. The weak section uses material with lower Young's Modulus or reduced cross-sectional dimensions to provide localized compliance for strain amplification, while the stiff section uses material with higher Young's Modulus to maintain structural integrity. This local differentiation of material properties enables simultaneous optimization of both measurement sensitivity and structural strength.
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 strain magnification patch provides higher resolution strain measurements by mechanically amplifying the measurable strain experienced by downhole tools, reducing the need for electrical magnification and minimizing noise, thus enhancing the accuracy of strain measurements in extreme drilling conditions.
Implementation Method 1
The weak section can be more deformable relative to the stiff section, thus magnifying the strain experienced by the downhole tool. The weak section can be thinner and/or narrower than the stiff section, thereby providing increased deformation relative to the stiff section
Data Source
AI summary
A strain magnification apparatus can have a first section and a second section coupled with the first section. The second section can have a lower stiffness relative to the first portion and a strain gauge coupled thereto. The first section is operable to be coupled to a tool experiencing strain and the tool is formed from a material having lower elasticity than the second section.