Gamma Detector Initial Gain Estimation via Voltage Sweep
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Solution Overview
Problem
Existing gamma detectors in well systems face challenges in accurately stabilizing gain due to temperature changes and other environmental factors, especially when dealing with naturally occurring low-intensity gamma radiation, which can lead to inaccurate measurements and inefficiencies in fine gain control.
Innovation Solution
A method for in-situ initial gain estimation of gamma detectors by sweeping through a range of high voltages, counting gamma events, and determining the knee point to set the initial gain, allowing for real-time or near real-time calibration and diagnostic analysis to identify potential issues with the detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fine gain control functions are used to stabilize gamma detector gain, then gain stabilization is achieved, but measurement accuracy deteriorates when dealing with low-intensity naturally occurring gamma radiation
Solution Approach 1:
The patent applies preliminary action by performing an initial gain estimation procedure before executing fine gain control functions. The system sweeps through a range of high voltages, counts gamma events at each voltage level, and determines a knee point to establish an initial gain value. This preliminary setup ensures the detector is properly configured for low-intensity radiation measurement before fine tuning begins, resolving the contradiction by preparing the system in advance for accurate low-level measurements.
2Measurement precision
If gamma detector gain is adjusted to account for temperature changes and environmental factors, then measurement accuracy is improved, but operational complexity increases
Solution Approach 1:
The patent implements self-service through an automated initial gain estimation process that performs the entire calibration sequence without manual intervention. The system automatically sweeps through voltage ranges, counts gamma events, identifies the knee point, and sets the initial gain value. This automation eliminates the need for manual calibration procedures while maintaining high measurement accuracy across varying temperature and environmental conditions.
3Adaptability or versatility
If the gamma detector is calibrated in real-time or near real-time, then adaptability to changing conditions is improved, but the time required for calibration increases
Solution Approach 1:
The patent applies periodic action by implementing initial gain estimation at scheduled intervals and triggered events. The system performs calibration during routine operations such as when the drill string is tripped in or out of the wellbore, or when temperature changes exceed predetermined thresholds. This periodic approach maintains adaptability to changing conditions while minimizing calibration time by only performing necessary adjustments at appropriate intervals rather than continuously.
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 enables accurate and efficient stabilization of gamma detector gain, improving measurement accuracy and speed, even in environments with low-intensity radiation, and provides diagnostic insights for detector maintenance and fault detection.
Implementation Method 1
counting detected gamma events at each high voltage data collection point using the gamma detector
Data Source
AI summary
The disclosure presents a process for determining an initial gain of a gamma detector located within a wellbore of a well system. The technique can utilize the subterranean formation characteristics at the gamma detector. The process can sweep, at a step value, across a determined high voltage range. At each sweep step, gamma events can be detected and counted over a detection time interval. The collected gamma events can then be utilized to perform an in-situ plateau test from which a high voltage can be determined, e.g., knee of the plateau curve. The determined high voltage can then be used as the initial gain. Additional fine gain control functions can be executed to further adjust the gain. In an alternative aspect, the collected gamma events can be utilized to perform diagnostics to infer faults or issues with the gamma detector assembly while it is down-hole.