Resolving the pore structure and sorption properties of methane in mudrocks - A small angle neutron scattering study

Small angle neutron scattering has been combined with supercritical methane sorption resulting in a collection of isothermal scattering curves for Opalinus Clay, Posidonia Shale and Eagleford Shale. Scattering data have been analyzed with respect to sorbed phase behavior for which a two- and three-phase model have been used. The two-phase model clearly indicates the formation of a sorbed phase of which properties like density and volume fraction change with pore size. Application of the three-phase model yields sorbed phase densities higher than the bulk density of methane as predicted by the equation of state provided by NIST. Current work focuses on implementing localized density calculations in order to quantify the effect of pore size on the sorbed phase properties.