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Updated: May 4, 2026
07:51
Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes
Published on: August 24, 2017
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Improved density estimation via pair production correction and experimental validation in neutron gamma logging
Abolfazl Rafizade1, Seyed Abolfazl Hosseini2
1Department of Energy Engineering, Sharif University of Technology, Tehran, 8639-11365, Iran. Abalfazl_rafizade@yahoo.com.
Scientific Reports
|May 2, 2026
Summary
This study presents a new neutron-gamma density (NGD) model that minimizes pair production errors. It improves density estimation accuracy, especially in geological formations with low hydrogen content.
Area of Science:
- Geophysics
- Nuclear Well Logging
- Computational Physics
Background:
- Neutron-gamma density (NGD) logging is crucial for geological formation analysis.
- Pair production effects can introduce significant errors in NGD-based density estimations.
- Accurate density measurements are vital for hydrocarbon exploration and reservoir characterization.
Purpose of the Study:
- To develop and validate an improved NGD model that mitigates pair production interference.
- To enhance the accuracy of density estimations, particularly in formations with low hydrogen content.
- To assess the influence of mudcake thickness and hydrogen weight fraction on NGD measurements.
Main Methods:
- Utilized MCNPX simulation software to model NGD tool interactions with geological formations.
- Analyzed neutron and gamma ray energy distributions and their response to varying parameters.
- Investigated the impact of mudcake thickness on gamma flux ratios.
- Conducted experimental benchmarking using a Californium-252 (Cf-252) source to validate simulation results.
Main Results:
- The improved NGD model effectively reduces errors associated with pair production.
- Demonstrated enhanced accuracy in density estimations for formations with hydrogen weight fractions below 10%.
- Simulation results were validated through experimental benchmarking, showing good agreement with real-world data.
Conclusions:
- The developed NGD model offers more accurate density measurements, particularly for low-hydrogen environments.
- The model shows promise for improving the reliability of NGD logging data.
- Further research may be beneficial to optimize the model for high hydrogen fraction scenarios.
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