Quantitative core analysis measurements using multi-nuclear Magnetic Resonance and Magnetic Resonance Imaging
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Date
2025-07
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University of New Brunswick
Abstract
Wettability, fluid saturation, and their spatial distribution critically influence fluid flow, recovery efficiency, and resource management in petroleum reservoirs. Traditional core analysis and wettability characterization methods, such as Dean-Stark extraction and Amott-Harvey tests, are invasive, time-consuming, and limited to end-state measurements. This dissertation advances the use of multi-nuclear Magnetic Resonance (MR) techniques - hydrogen (1H), carbon-13 (13C), and sodium-23 (23Na) MR/MRI - to address these limitations and better understand fluid-rock interactions in porous media.
A new saturation measurement technique is introduced using 1H MR to quantify total fluid content and 13C MR to measure hydrocarbons, enabling direct water and oil saturation determinations without Dean-Stark extraction. Validation against conventional methods showed excellent agreement and improved efficiency. These methods were further extended to image hydrocarbon saturation using 13C MRI, revealing fluid distribution heterogeneity, capillary effects, and wettability-dependent patterns. These methods provide a valuable tool for understanding enhanced oil recovery (EOR) processes compared to conventional X-ray methods.
This research also characterizes crude oils using combined 1H and 13C MR. Signal intensities per volume were consistent across diverse oil samples, allowing oil volumes to be calculated directly without specialized reference materials. Additionally, 13C MR relaxation times were sensitive to wettability changes, providing hydrocarbon-specific, non-invasive wettability assessments.
1H MR was employed to study crude oil emulsion instability, demonstrating its versatility in capturing bulk and spatially resolved relaxation data. These insights inform our understanding of the dynamics of dispersed and continuous phases over time.
Finally, the phenomenon of salt precipitation during gas injection and drying was monitored using 23Na MR/MRI. This process, of critical interest in CO2 storage and gas production, was analyzed via 23Na relaxation measurements and 1D imaging to distinguish dissolved and precipitated NaCl phases.
In summary, this dissertation validates 1H, 13C, and 23Na MR methodologies for comprehensive, non-invasive core analysis. These advances enhance reservoir characterization, improve understanding of fluid-rock interactions, and support strategies for effective EOR and subsurface fluid management.