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Determination of closed porosity in rocks by small‐angle neutron scattering
Author(s) -
Bahadur Jitendra,
Medina Cristian R.,
He Lilin,
Melnichenko Yuri B.,
Rupp John A.,
Blach Tomasz P.,
Mildner David F. R.
Publication year - 2016
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576716014904
Subject(s) - small angle neutron scattering , porosity , neutron scattering , scattering , neutron , intensity (physics) , materials science , volume fraction , volume (thermodynamics) , small angle scattering , porous medium , mineralogy , geology , optics , composite material , nuclear physics , thermodynamics , physics
Small‐angle neutron scattering (SANS) and ultra‐small‐angle neutron scattering (USANS) have been used to study a carbonate rock from a deep saline aquifer that is a potential candidate as a storage reservoir for CO 2 sequestration. A new methodology is developed for estimating the fraction of accessible and inaccessible pore volume using SANS/USANS measurements. This method does not require the achievement of zero average contrast for the calculation of accessible and inaccessible pore volume fraction. The scattering intensity at high Q increases with increasing CO 2 pressure, in contrast with the low‐ Q behaviour where the intensity decreases with increasing pressure. Data treatment for high‐ Q scattering at different pressures of CO 2 is also introduced to explain this anomalous behaviour. The analysis shows that a significant proportion of the pore system consists of micropores (<20 Å) and that the majority (80%) of these micropores remain inaccessible to CO 2 at reservoir pressures.