Interfacial tension of CO2 and crude oils under high pressure and temperature

•Interfacial tension between CO2 and crude oil is affected by intermolecular forces.•For CO2 + hexadecane system, the phenomenon of miscibility is observed.•For crude oil A, the predicted minimum miscibility pressure (MMP) is 26.40 MPa.•For crude oil B, the predicted minimum miscibility pressure (MMP) is 24.00 MPa,

The interfacial tension data between CO2 and reservoir crude oils were measured by the pendant-drop method and the axisymmetric drop shape analysis (ADSA) under high pressure and temperature up to 45 MPa and 412.15 K respectively. The results show that at beginning, the interfacial tension between CO2 and crude oils decreases rapidly with pressure being increased, and then the interfacial tension decreases quite slowly with increasing of pressure because of heavy components in the crude oils. There is no ultra-low or zero interfacial tension obtained for CO2 + crude oil systems. For comparison, the interfacial tensions between CO2 and hexadecane at 318.15 K were also determined. The results show that for CO2 + hexadecane system, the vanishing interfacial tension and miscible phenomenon are observed.

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