Determination of Closed Porosity in Rocks by Small-Angle Neuron Scattering

Published

October 3, 2016

Author(s)

Jitendra Bahadur, Christian R. Medina, Lilin He, Yuri B. Melnichenko, John A. Rupp, Tomasz P. Blach, David F. Mildner

Abstract

Small-angle neutron (SANS) and ultra small-angle neutron scattering (USANS) has been used to study a carbonate rock from a deep saline aquifer that is a potential candidate for storage reservoir for CO₂ 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 achieving zero average contrast (ZAC)for the calculation of accessible and inaccessible pore volume fraction. The scattering intensity at high-Q increases with increasing CO₂ pressure in contrast to the low-Q behaviour where intensity decreases with pressure. Data treatment for high-Q scattering at different pressure of CO₂ is also introduced to explain this anomalous behaviour. The analysis has been shown that a significant portion of the pore system are micropores (<2nm) and that the majority (80%) of these micropores remains inaccessible to CO₂ at reservoir pressures.

Citation

Journal of Applied Crystallography

Volume

49

Issue

6

Pub Type

Journals

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Keywords

closed porosity, CO2 storage reservoir, fractal pores, polydisperse micropores, pore size distribution, scattering length density, small-angle neutron scattering, supercritical CO2

Citation

Bahadur, J. , Medina, C. , He, L. , Melnichenko, Y. , Rupp, J. , Blach, T. and Mildner, D. (2016), Determination of Closed Porosity in Rocks by Small-Angle Neuron Scattering, Journal of Applied Crystallography, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=921370 (Accessed November 3, 2025)