A multi-dimensional experiment for characterization of pore structure heterogeneity using NMR

Area of Science:

• Geophysics
• Materials Science
• Nuclear Magnetic Resonance Spectroscopy

Background:

• Internal magnetic fields in porous media are influenced by static magnetic fields, magnetic susceptibility differences, and pore network geometry.
• Understanding these fields is crucial for characterizing porous structures and their properties.

Purpose of the Study:

• To develop a novel multi-dimensional nuclear magnetic resonance (NMR) experiment to probe internal magnetic fields.
• To measure dynamic correlations involving the internal magnetic field and its dependence on porous network geometry.
• To demonstrate the utility of these correlations in assessing pore structure heterogeneity.

Main Methods:

• A novel multi-dimensional NMR experiment was designed and implemented.
• The experiment measures dynamic correlations, including internal gradient-pore size, internal gradient-magnetic susceptibility difference, internal gradient-longitudinal relaxation, and longitudinal relaxation-magnetic susceptibility difference.
• The study addresses the spatial averaging of measured properties.

Main Results:

• The developed NMR experiment successfully measures multiple dynamic correlations simultaneously.
• These correlations serve as indicators of pore structure heterogeneity.
• Methods for evaluating and accounting for spatial averaging effects in the analysis of NMR data were demonstrated.

Conclusions:

• The novel NMR approach provides insights into the relationship between internal magnetic fields and porous material properties.
• The technique is effective in identifying and characterizing pore structure heterogeneity.
• Accounting for spatial averaging is essential for accurate interpretation of the results.