Nuclear Spectroscopy Background Correction via Segmentation
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Solution Overview
Problem
Nuclear spectroscopy techniques like neutron-gamma spectroscopy face challenges in accurately determining formation types during drilling due to environmental variations and background interference from drilling tools and mud, which affect the accuracy of elemental concentration measurements.
Innovation Solution
A method and system using a nuclear spectroscopy tool with a neutron source and gamma ray detector that emits neutrons to generate spectra from the formation, tool, and mud, analyzing the energy spectrum with multiple standards differentiated by neutron interaction locations to estimate formation aspects, accounting for environmental impacts and background interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If neutron-gamma spectroscopy is used to determine formation properties, then elemental concentration measurements can be obtained, but background interference from tool and mud elements reduces measurement accuracy
Solution Approach 1:
The patent segments the background spectrum into multiple distinct sources (tool background, mud background, formation background) and develops separate correction methods for each. By identifying and characterizing the unique spectral signatures of tool elements and mud elements, the system can selectively subtract each background component to isolate the formation signal, thereby resolving the measurement accuracy problem caused by composite background interference.
Solution Approach 2:
The patent introduces environmental measurements (neutron flux, gamma ray flux, borehole conditions) as intermediary parameters that mediate between the raw spectroscopy data and the final formation analysis. These intermediaries allow the system to model and correct for background effects dynamically, separating the formation signal from tool and mud interference through mathematical relationships established by the environmental measurements.
2Adaptability or versatility
If environmental variations in formation conditions are present, then diverse geological scenarios can be measured, but spectral measurements are affected by changing environmental parameters
Solution Approach 1:
The patent implements dynamic correction methods that adapt to changing environmental conditions during measurement. By continuously measuring environmental parameters (borehole size, fluid density, formation density, neutron flux) and using these to dynamically adjust the background subtraction and spectral analysis, the system maintains measurement accuracy across diverse geological scenarios while preserving adaptability to different formation types.
Solution Approach 2:
The patent changes the parameters used in spectral analysis based on measured environmental conditions. By adjusting correction factors, standard spectra, and analysis models according to actual borehole and formation parameters, the system optimizes measurement accuracy for each specific environmental condition while maintaining versatility across different geological settings.
3Measurement precision
If multiple standards differentiated by neutron interaction location are used, then background contributions can be separated, but analysis complexity increases
Solution Approach 1:
The patent segments the spectral analysis into distinct components corresponding to different neutron interaction locations (tool, mud, formation). By creating separate standard spectra for each location and developing targeted correction algorithms for each segment, the system achieves accurate background separation while organizing the complexity into manageable, modular analysis steps that can be implemented systematically.
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 enhances the accuracy of formation estimation by effectively separating and subtracting background contributions, leading to more precise measurements of elemental concentrations and improved drilling decisions.
Implementation Method 1
neutron-gamma spectroscopy, which uses neutrons to create excited states in a nucleus which then may decay via emission of one or more gamma rays
Implementation Method 2
a gamma ray detector that is configured to detect an energy spectrum of gamma rays induced by the emitted neutrons
Data Source
AI summary
A method for estimating an aspect of a formation using a nuclear spectroscopy tool includes placing a nuclear spectroscopy tool including a neutron source and a gamma ray detector into a borehole and performing a plurality of environmental measurements. Neutrons are emitted from the nuclear spectroscopy tool such that some of the neutrons generate gamma rays from a formation adjacent the nuclear spectroscopy tool, some of the neutrons generate gamma rays from elements within the nuclear spectroscopy tool and some of the neutrons generate gamma rays from an element in the drilling mud. An energy spectrum of gamma rays induced by the emitted neutrons can be detected with the tool and analyzed using a combination of standard spectra including at least two sub-standards that represent a common element or group of elements and that are differentiated based on location of neutron interaction, such as where the neutrons thermalize.