Measurement and modelling of interfacial tension in methane/water and methane/brine systems at reservoir conditions

Molecular Dynamics Simulation Study of Carbon Dioxide, Methane, and Their Mixture in the Presence of Brine

“…The appearance of a maximum in the density profile of methane (dashed line) near the interface is in agreement with other studies. 19,[21][22][23] These studies have shown that the local adsorption of methane molecules which is proportional to the area under the methane peak generally decreased with increasing temperature and pressure. Furthermore, the position of the peak in the density profile of methane shifted towards the methane-rich phase with increasing pressure.…”

“…16,19,21 The minimum in the IFT was obtained at pressures around the transition point between the positive and negative relative adsorption of methane molecules. 19,21 The variation of the IFT values of the CH 4 −brine system with pressure and temperature is similar to that observed for the corresponding CH 4 −water S4). We also see that, independent of temperature, the slope for the salt dependence of IFT is about 2.2 mN/(m mol kg −1 ) in the pressure range 7-25 MPa (see Fig.…”

“…However, at relatively high pressures the IFT values exhibited a moderate increase with increasing pressures. 16,19,21 The inversion of the IFT dependence with pressure and the observation of an IFT minimum occurred for pressures around the transition point between the positive and negative relative adsorption of methane molecules with respect to water molecules in the interfacial region. 19,21 The density gradient theory (DGT) was able to predict the measured increase of the IFT of the methane-water system due to the presence of up to 10 wt% NaCl.…”

“…11,12 The study of interactions between CO 2 and water is important as a reference point for the understanding of a large variety of interfacial processes, for instance, those including surfactants. 13,14 A number of experimental, [15][16][17][18][19] theoretical, [19][20][21] and simulation [21][22][23] studies have been carried out to determine the interfacial properties of CH 4 −water and CH 4 −brine systems. In general, the results of these studies showed a reduction of the IFT with increasing pressure.…”

“…19,21 The density gradient theory (DGT) was able to predict the measured increase of the IFT of the methane-water system due to the presence of up to 10 wt% NaCl. 19 Several experimental, 15,[24][25][26][27][28][29][30][31][32][33] theoretical, 28,31,[33][34][35][36][37] and simulation 24,37-44 studies have also been performed to determine the interfacial properties of CO 2 −water and CO 2 −brine systems. Overall, IFT decreased with both temperature and pressure in the low-pressure range (gaseous CO 2 ) but was mostly independent of pressure at high pressures (liquid or supercritical CO 2 ).…”