Interfacial tension and contact angle measurements for hydrogen-methane mixtures/brine/oil-wet rocks at reservoir conditions

Abstract

In this study, we measured the interfacial tensions (IFTs) of brine/hydrogen-methane (H2–CH4) mixtures. We also measured the static contact angles of H2–CH4 mixtures in contact with brine and oil-wet sandstone and limestone rocks at reservoir conditions. The measurements were conducted using pendant drop and rising/captive bubble techniques. The techniques were first validated for pure gas/brine IFT and contact angle systems. Then, the impacts of temperature and H2–CH4 mixture fraction in contact with oil-wet rocks were investigated systematically. IFT values of H2–CH4 mixture/brine diminished with increasing temperature and decreasing hydrogen fraction. It is revealed that, under the studied conditions, H2–CH4 mixtures exhibit comparable weakly water-wet behavior on oil-wet sandstone and limestone rocks with contact angles ranged within [52.42°-71.1°] independent of temperature. The results also indicated that IFT of H2–CH4 mixture/brine decreases with increased temperature and methane fraction. Finally, the mechanisms accountable for the observed rock-fluid interaction behaviors at different conditions were discussed.