Retractable Support Arm for Borehole Centralization
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Solution Overview
Problem
Existing oil exploration tools face challenges in accurately measuring formation pressure and extracting fluid samples due to misalignment during setting and sealing in boreholes of varying sizes, leading to measurement errors.
Innovation Solution
A sampling-by-pushing system equipped with a centralizing device featuring a retractable support arm that extends to contact the borehole wall, ensuring the setting-by-pushing mechanism is centered, combined with a hydraulic control system for precise extension and retraction of the support arm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the tool is lowered into the borehole for setting and sealing, then the measurement and sampling function is enabled, but the tool may not be centered due to different borehole sizes, causing measurement errors
Solution Approach 1:
The support arm is designed as a retractable dynamic structure that can extend and retract based on borehole diameter. When extended, it contacts the borehole wall to center the tool; when retracted, it allows the tool to be lowered and retrieved. This dynamic adjustment resolves the contradiction between needing precise centering for accurate measurement and needing adaptability to different borehole sizes.
2Adaptability or versatility
If the tool structure is fixed without centralizing device, then the device complexity is reduced, but the tool cannot be centered in boreholes of varying sizes, affecting setting effect
Solution Approach 1:
The support arm is nested within the tool body when retracted, occupying minimal space. When deployment is needed, it extends outward to contact the borehole wall. This nesting approach provides adaptability to different borehole sizes while minimizing the increase in device complexity, as the centralizing mechanism is integrated into the existing tool structure.
3Manufacturing precision
If the support arm is extended to contact the borehole wall for centering, then the tool positioning accuracy is improved, but the device complexity increases due to extension and retraction mechanism
Solution Approach 1:
The support arm utilizes the pressure differential between the interior and exterior of the tool to achieve automatic extension and retraction. When the tool is lowered into the borehole, external pressure pushes the support arm outward to contact the wall and center the tool. During retrieval, internal pressure retracts the arm. This self-service mechanism reduces the need for complex external actuation systems while maintaining centering precision.
Data Source
AI summary
A sampling-by-pushing system includes a setting-by-pushing mechanism and a centralizing device. The setting-by-pushing mechanism is connected with the centralizing device through a connecting pipe, and is configured to be set and sealed in a borehole. The centralizing device includes a base body and a retractable support arm arranged on the base body. The support arm is configured to be in contact with the wall of the borehole so as to position the setting-by-pushing mechanism in the center of the borehole.