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Pulsed Neutron Logging Frameworks for Co₂ Plume and Well Integrity Surveillance in Mature Asset Conversion
Subject area: Science,Engineering and Technology · Area of research: Chemistry
DOI: https://doi.org/10.64388/IREV10I1-1719714
Abstract
The world is moving towards CCS and considerable interest has been created in the re-use of old oil and gas wells for CO₂ injection and storage. This has many economic and logistics benefits, but also creates a dual monitoring need: not only tracking the migration of the subsurface CO₂ plume but also ensuring the long-term mechanical integrity of the converted well systems. Permanently cased wellbores are an area of great monitoring need that conventional open-hole wireline techniques are unable to meet. This paper offers a proposed concept of a synthesized framework for the deployment of PNL as a dual-purpose surveillance tool in a converted hydrocarbon producing well for CO₂ injection/CO₂ storage. The framework has been developed based on the field deployments and analyses of the various international CCS projects, such as Ketzin (Germany), the Otway project (Australia), the Illinois Basin-Decatur Project (USA) and simulation work in China and Romania, and combines the two main measurement modalities of PNL, the macroscopic thermal neutron capture cross-section (Sigma, Σ) and the carbon/oxygen (C/O) ratio log. These measurements can be combined to provide quantitative estimation of CO₂ saturation, identification of plume boundaries and detection of fluid migration behind casing in a single cased hole tool deployment. The paper also makes a synthesis of multi-detector acquisition configurations, forward modeling using Monte Carlo methods and the new emerging machine learning interpretation schemes that can improve the diagnostic accuracy of PNL. Importantly, the multi-purpose nature of PNL—the geochemical plume tracking and structural integrity survey—makes it an essential part of a comprehensive CCS portfolio. The framework takes the research forward in the systematic nature of closing the gap in the monitoring for mature asset conversion scenarios.
Keywords
Carbon Capture and Storage (CCS), Pulsed Neutron Logging (PNL), CO₂ Plume Monitoring, Well Integrity, Mature Asset Conversion, Sigma Logging, Carbon/Oxygen (C/O) Ratio Logging.
How to cite this paper
@article{1719714,
author = {Imorgiemeh, Akagbosu Pius, Elvis John Ighodalo},
title = {Pulsed Neutron Logging Frameworks for Co₂ Plume and Well Integrity Surveillance in Mature Asset Conversion},
journal = {Iconic Research And Engineering Journals},
year = {2026},
volume = {10},
number = {1},
pages = {1355-1364},
issn = {2456-8880},
url = {https://www.irejournals.com/formatedpaper/1719714.pdf},
abstract = {The world is moving towards CCS and considerable interest has been created in the re-use of old oil and gas wells for CO₂ injection and storage. This has many economic and logistics benefits, but also creates a dual monitoring need: not only tracking the migration of the subsurface CO₂ plume but also ensuring the long-term mechanical integrity of the converted well systems. Permanently cased wellbores are an area of great monitoring need that conventional open-hole wireline techniques are unable to meet. This paper offers a proposed concept of a synthesized framework for the deployment of PNL as a dual-purpose surveillance tool in a converted hydrocarbon producing well for CO₂ injection/CO₂ storage. The framework has been developed based on the field deployments and analyses of the various international CCS projects, such as Ketzin (Germany), the Otway project (Australia), the Illinois Basin-Decatur Project (USA) and simulation work in China and Romania, and combines the two main measurement modalities of PNL, the macroscopic thermal neutron capture cross-section (Sigma, Σ) and the carbon/oxygen (C/O) ratio log. These measurements can be combined to provide quantitative estimation of CO₂ saturation, identification of plume boundaries and detection of fluid migration behind casing in a single cased hole tool deployment. The paper also makes a synthesis of multi-detector acquisition configurations, forward modeling using Monte Carlo methods and the new emerging machine learning interpretation schemes that can improve the diagnostic accuracy of PNL. Importantly, the multi-purpose nature of PNL—the geochemical plume tracking and structural integrity survey—makes it an essential part of a comprehensive CCS portfolio. The framework takes the research forward in the systematic nature of closing the gap in the monitoring for mature asset conversion scenarios.},
keywords = {Carbon Capture and Storage (CCS), Pulsed Neutron Logging (PNL), CO₂ Plume Monitoring, Well Integrity, Mature Asset Conversion, Sigma Logging, Carbon/Oxygen (C/O) Ratio Logging.},
month = {July},
doi = {https://doi.org/10.64388/IREV10I1-1719714}
}