Pivotable Sensor Pad for Non-Circular Borehole Logging
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Solution Overview
Problem
Logging tools with sensor pads face poor contact alignment and measurement errors in non-circular borehole sections due to radial extension, leading to suboptimal contact with the borehole wall, which affects the accuracy of density and micro-resistivity logging.
Innovation Solution
The implementation of a pivotable and extendable sensor pad system that can rotate and tilt to align better with non-circular borehole walls, ensuring consistent contact and improving measurement quality by using linkage assemblies and actuators to apply force and adjust position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a radial sensor pad extension is used in a non-circular borehole, then the logging tool can maintain a simple structure, but the contact alignment between the pad and borehole wall deteriorates
Solution Approach 1:
The sensor pad is made pivotable about the tool axis, transforming it from a static radial extension to a dynamic component that can adjust its orientation. This allows the pad to rotate and align with the non-circular borehole wall geometry, improving contact alignment while maintaining measurement precision
Solution Approach 2:
The orientation angle of the sensor pad is changed as a variable parameter. By allowing the pad to rotate to different angular positions, the system adapts to the varying geometry of non-circular boreholes, optimizing contact alignment for each specific borehole configuration
2Measurement precision
If the sensor pad is made pivotable to improve contact alignment, then measurement precision improves, but device complexity increases
Solution Approach 1:
The sensor pad assembly is segmented into a modular structure with distinct components: the pad itself, the pivot mechanism, and the actuation system. This segmentation allows for independent optimization of each component and simplifies the overall design by breaking down the complex pivotable mechanism into manageable parts
Solution Approach 2:
A pivot mechanism serves as an intermediary between the simple radial extension and the complex fully-articulated system. This intermediate solution provides the necessary rotational capability for alignment while maintaining structural simplicity through a single-degree-of-freedom rotation about the tool axis
Data Source
AI summary
An apparatus for logging in a borehole comprises a longitudinal body. A pad is coupled to and radially extendable from the longitudinal body toward a wall of the borehole. The radially extendable pad comprises a sensor. The radially extendable pad is rotatable about a longitudinal axis by a predetermined angle. A method for logging a borehole comprises extending a longitudinal body into the borehole; disposing a sensor in a radially extendable pad; coupling the radially extendable pad to the longitudinal body such that the radially extendable pad is rotatable about a longitudinal axis by a predetermined angle; and extending the radially extendable and rotatable pad toward a wall of the borehole.