Natural fluids consisting of light hydrocarbons adsorb, desorb, migrate and react at mineral surfaces and within pores � most of which lie in the mesoporous length scale. Shale reservoirs enriched with natural gas liquids - ethane, propane and butane are being targeted aggressively to improve profitability of drilling. There is a knowledge gap with respect to the effects of pore size, temperature, pressure and mineral composition on the sorption and transport properties of light hydrocarbons confined to mesoporous matrices.Excess sorption isotherms of supercritical ethane in mesoporous CPG-10 silica with nominal pore sizes of 7.5 nm and 35 nm were measured gravimetrically at 35oC and 50oC in the reduced density range of 0 to 1.75. Formation of broad maxima in the excess sorption was observed at fluid densities below the bulk critical density of ethane. Positive values of excess sorption were measured below the bulk critical density indicating an enriched confined fluid at low pressures. The excess sorption dropped to negative values for the larger pores beyond the bulk critical density whereas the smaller pores stayed enriched. The same material was studied previously with supercritical CO2 as the fluid (G. Rother et al, J. Phys. Chem. C (2011) 116, 917). A qualitative as well as quantitative comparison between the behavior of CO2 and ethane revealed notable differences in the interaction of the two fluids with the silica matrix.

Confinement behavior of ethane in mesoporous CPG-10 silica

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.