High-Pressure Interfacial Tension of the Brazilian Crude Oil - CO2 System

Enhanced oil recovery (EOR) processes are once again becoming increasingly important to the petroleum industry.  After the primary and secondary recovery, a typical residual oil saturation in a light or medium oil reservoir is in the range of 50–60% of the original oil-in-place (OOIP).  In the EOR, gases such carbon dioxide (CO₂) and natural gas are injected in the petroleum reservoirs for crude oil recovering.  It is well known that the interfacial tension between the injected gas and the crude oil has a major influence on the efficiency of displacement of oil by gas.  When the injected gas becomes miscible with the crude oil, which means that there is no interface between the injected and displaced phases, the oil is displaced with maximum efficiency, resulting in high recoveries.

In this study, an experimental setup is established to measure the dynamic and equilibrium interfacial tensions of the Brazilian crude oil + CO₂ system under various conditions using the pendant drop technique.  This experimental technique is used to determine the interfacial tension of the above system at different pressures and various isotherms.  The measured interfacial tension data will provide a better understanding of the interfacial interactions between the crude oil and CO₂ and, consequently, to improve the economics of the gas injection process.