Determination of Closed Porosity in Rocks by Small-Angle Neuron Scattering
Jitendra Bahadur, Christian R. Medina, Lilin He, Yuri B. Melnichenko, John A. Rupp, Tomasz P. Blach, David F. Mildner
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.
closed porosity, CO2 storage reservoir, fractal pores, polydisperse micropores, pore size distribution, scattering length density, small-angle neutron scattering, supercritical CO2
, Medina, C.
, He, L.
, Melnichenko, Y.
, Rupp, J.
, Blach, T.
and Mildner, D.
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 December 4, 2023)