Direct Measure of the Dense Methane Phase in Gas Shale Organic Porosity by Neutron Scattering

We report the first direct measurements of methane density in shale gas using small-angle neutron scattering. At a constant pressure, the density of methane in the inorganic pores is similar to the gas bulk density of the system conditions. In contrast, the methane density is 2.1 +/- 0.2 times greater in the organic mesopores. Classical density functional theory calculations show that this excess density in the organic pores persists to elevated temperatures, typical of shale gas reservoir conditions, providing new insight into the hydrocarbon storage mechanisms within these reservoirs.