The role of CO2 and ion type in the dynamic interfacial tension of acidic crude oil/carbonated brine

Abstract

Abstract The effects of CO2 and salt type on the interfacial tension (IFT) between crude oil and carbonated brine (CB) have not been fully understood. This study focuses on measuring the dynamic IFT between acidic crude oil with a total acid number of 1.5 mg KOH/g and fully CO2-saturated aqueous solutions consisting of 15,000 ppm of KCl, NaCl, CaCl2 and MgCl2 at 30 °C and a wide range of pressures (500–4000 psi). The results of IFT measurements showed that solvation of CO2 into all the studied aqueous solutions led to an increase in IFT of acidic crude oil (i.e., comparison of IFT of crude oil/CB and crude oil/brine), while no significant effect was observed for pressure. In contrast, the obtained results of studied salts indicated a positive effect on the IFT reduction of acidic crude oil/carbonated water (CW) (i.e., comparison of IFT of crude oil/CB and crude oil/CW).

Keywords

• Carbonated brine
• Interfacial tension
• Crude oil
• Enhanced oil recovery (EOR)
• CO2 sequestration