Gamma Logging Tool Calibration via Angular Orientation
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Solution Overview
Problem
The existing calibration methods for gamma logging tools require multiple calibrators with different circumferences, increasing equipment costs and logistical complexity due to the need for standardization of gamma radiation measurements across tools of varying sizes.
Innovation Solution
A calibrator is positioned on the gamma logging tool at three angular orientations spaced 120 degrees apart, allowing for the determination of a combined detector count rate that is independent of the initial angular orientation, enabling the use of a single calibrator for tools of different sizes and circumferences, and a calibration gain factor is calculated to adjust measurements for accurate API-based radiation assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple calibrators with different circumferences are used to wrap entirely around gamma logging tools, then gamma radiation measurements can be standardized across tools of varying sizes, but equipment cost and logistical complexity increase
Solution Approach 1:
A single calibrator is designed to calibrate gamma logging tools of different circumferences by positioning it at multiple angular orientations (0°, 120°, 240°) on the tool. This eliminates the need for multiple calibrators with different sizes, making one calibrator universal for all tool sizes while maintaining measurement standardization.
Solution Approach 2:
Instead of varying the calibrator's circumference (one-dimensional solution) to match different tool sizes, the invention introduces angular orientation as a new dimension. The calibrator is positioned at three specific angular orientations around the tool, allowing a single calibrator to effectively calibrate tools of any circumference.
2Measurement precision
If multiple calibrators with different circumferences are maintained, then accurate calibration is achieved for each tool size, but equipment cost increases
Solution Approach 1:
One calibrator performs the function of multiple calibrators by being positioned at three different angular orientations. This universal approach maintains calibration accuracy for tools of all sizes while reducing the quantity of calibrators from multiple units to a single unit.
Solution Approach 2:
The functionality of multiple calibrators (with different circumferences) is merged into a single calibrator through the angular orientation method. The three positions at 0°, 120°, and 240° effectively combine the calibration capabilities that would otherwise require three separate calibrators.
3Reliability
If a calibrator is wrapped entirely around the gamma logging tool, then complete coverage is achieved, but the requirement for multiple calibrators increases equipment complexity
Solution Approach 1:
Instead of achieving complete coverage by increasing calibrator circumference, the invention uses angular orientation as an additional dimension. Positioning the calibrator at three orientations (0°, 120°, 240°) provides comprehensive calibration coverage for all tool sizes without requiring the calibrator to wrap entirely around the tool.
Solution Approach 2:
A single calibrator positioned at multiple angular orientations achieves the same reliability and completeness as multiple calibrators wrapped around the tool. This universal positioning method maintains calibration completeness while eliminating the need for multiple calibrators.
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 approach simplifies the calibration process, reduces the need for multiple calibrators, and ensures accurate gamma radiation measurements across different gamma logging tools, facilitating cost-effective and efficient geologic formation evaluation.
Implementation Method 1
The calibrator has radioactive material uniformly distributed inside which emits gamma radiation
Implementation Method 2
A detector in the gamma logging tool responds to the gamma radiation emitted by the calibrator by generating one or more electrical pulses
Data Source
AI summary
A calibrator is positioned on a logging tool at an angular orientation with respect to the logging tool. The calibrator has a radioactive source of gamma radiation distributed inside the calibrator. A first detector count rate is determined based on a detector in the logging tool detecting gamma radiation. One or more of the calibrator and logging tool is rotated by a first number of degrees. A second detector count rate is determined based on the detector in the logging tool detecting gamma radiation. One or more of the calibrator and logging tool is rotated by second number of degrees. A third detector count rate is determined based on the detector in the logging tool detecting gamma radiation. The first, second, and third detector count rates are averaged to determine a calibration gain factor based on the average detector count rate and a known indication of gamma radiation emitted by the calibrator.