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Characterization of fluid distributions in porous media by NMR techniques
Author(s) -
Liaw HsieKeng,
Kulkarni Raghavendra,
Chen Songhua,
Watson A. Ted
Publication year - 1996
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690420223
Subject(s) - porous medium , porosimetry , tikhonov regularization , porosity , chemistry , materials science , analytical chemistry (journal) , chromatography , mathematics , composite material , inverse problem , mathematical analysis
Nuclear magnetic resonance (NMR) spin‐lattice relaxation measurements are used to investigate pore structures and fluid phase distributions in porous media. A new method for estimating relaxation time distribution functions from measured relaxation data is presented using a B‐spline basis to represent the distribution function and Tikhonov regularization to stabilize the estimation problem. Surface relaxivity, which is required to convert relaxation time distributions to pore‐size distributions of fluid phase distributions at partial saturations, is determined using pore volume‐to‐surface‐area ratios estimated by NMR diffusion measurements. This approach was validated by analyzing certain model porous media with known pore volume‐to‐surface‐area ratios. The method is demonstrated by determining pore‐size and fluid phase distributions of sandstone and carbonate samples, as well as by comparing the pore‐size distributions of chalk samples obtained by this methodology with those estimated by mercury porosimetry.