title: Angstrom-to-millimeter characterization of sedimentary rock microstructure.
abstract: Backscatter SEM imaging and small-angle neutron scattering (SANS) data are combined within a statistical framework to quantify the microstructure of a porous solid in terms of a continuous pore-size distribution spanning over five orders of magnitude of length scale, from 10 A to 500 microm. The method is demonstrated on a sample of natural sandstone and the results are tested against mercury porosimetry (MP) and nuclear magnetic resonance (NMR) relaxation data. The rock microstructure is fractal (D=2.47) in the pore-size range 10 A-50 microm and Euclidean for larger length scales. The pore-size distribution is consistent with that determined by MP. The NMR data show a bimodal distribution of proton T(2) relaxation times, which is interpreted quantitatively using a model of relaxation in fractal pores. Pore-length scales derived from the NMR data are consistent with the geometrical parameters derived from both the SEM/SANS and MP data. The combined SANS/BSEM method furnishes new microstructural information that should facilitate the study of capillary phenomena in hydrocarbon reservoir rocks and other porous solids exhibiting broad pore-size distributions.
authors.affiliation: Geoscience Australia, GPO Box 378, Canberra City, Australian Capital Territory 2601, Australia. andrezej.radlinski@ga.gov.au
authors.forename: A P
authors.initials: AP
authors.lastname: Radlinski
authors.forename: M A
authors.initials: MA
authors.lastname: Ioannidis
authors.forename: A L
authors.initials: AL
authors.lastname: Hinde
authors.forename: M
authors.initials: M
authors.lastname: Hainbuchner
authors.forename: M
authors.initials: M
authors.lastname: Baron
authors.forename: H
authors.initials: H
authors.lastname: Rauch
authors.forename: S R
authors.initials: SR
authors.lastname: Kline