Borehole Logging Reference Detector for Real-Time X-Ray Calibration
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Solution Overview
Problem
The instability of x-ray source tubes introduces variability into borehole logging data, affecting the accuracy of formation density measurements, which cannot be adequately compensated for using existing methods that control the source tube or formation-facing detectors.
Innovation Solution
A reference detector is used to monitor the x-ray source output and adjust the formation-facing detectors' counts based on its output, employing a feedback loop and temperature-dependent calibration tables to correct for source tube variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If x-ray source tubes are used to replace radio-active isotope-based radiation sources, then the safety and regulatory compliance are improved, but the measurement stability and data accuracy deteriorate due to source tube output instability
Solution Approach 1:
The patent implements a feedback mechanism where a reference detector continuously monitors the x-ray source output, and the measured variations are used to adjust the calibration constants of formation-facing detectors in real-time, compensating for source instability
Solution Approach 2:
A reference detector is introduced as an intermediary component that indirectly measures source output variations without being directly exposed to the full radiation field, allowing calibration corrections to be applied to formation-facing detectors
2Reliability
If feedback control is implemented to stabilize x-ray source output, then the measurement stability is improved, but the device complexity increases due to additional control circuits and reference detectors
Solution Approach 1:
The reference detector serves as a simplified intermediary that provides source output information without requiring complex direct control of the x-ray tube, enabling indirect stabilization through calibration constant adjustment
Solution Approach 2:
Instead of controlling physical parameters of the x-ray source directly, the system changes the calibration constant parameters of the detectors based on reference detector measurements, achieving stabilization through parameter adjustment rather than physical control
3Measurement precision
If calibration constants are adjusted in real-time based on reference detector output, then the measurement accuracy is improved, but the data processing complexity increases
Solution Approach 1:
Calibration constant corrections are calculated and applied in real-time before formation density computation, ensuring that corrected counts are used in subsequent processing without requiring complex post-processing adjustments
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
Ensures high accuracy in formation density measurements by stabilizing the x-ray source output, allowing for reliable data correction and consistent statistical output across different ambient temperatures.
Implementation Method 1
a reference detector, wherein the reference detector uses a shielding to attenuate the radiation emanating directly from the source
Implementation Method 2
the reference detector uses a shielding to attenuate the radiation emanating directly from the source
Implementation Method 3
any variation in that data is a result of the change in scattering and attenuation properties of the formation itself
Data Source
Figure 1
Figure 2~3
AI summary
An x-ray based litho-density tool for measurement of formation surrounding a borehole is provided, the tool including at least an internal length comprising a sonde section, wherein said sonde section further comprises an x-ray source; at least one radiation measuring detector; at least one source monitoring detector; a plurality of sonde-dependent electronics; and a reference detector, wherein the reference detector is used to monitor the output of the x-ray source such that the reference detector's output effects corrections to the outputs of the detectors used to measure the density of the materials surrounding the borehole in order to correct for variations in the x-ray source output. Tool logic electronics, PSUs, and one or more detectors used to measure borehole standoff such that other detector responses may be compensated for tool standoff are also provided. Shielding, through-wiring, wear-pads that improve the efficacy and tool functionality are also described and claimed.