Experimental Studies on the Performance of Palm-Oil and Petroleum Based Surfactant in High Salinity Reservoir

Abstract

The use of surfactant in tertiary oil recovery is very promising effort to mobilize the remaining oil by its ability to influence the properties of fluid and rock. Surfactants are injected to maximize the performance by lowering the interfacial tension between water and oil in the reservoir. Different types of surfactants have been evaluated and selected after series of evaluation steps. In this paper, the performance of palm-oil based surfactant (methyl ester sulfonated) in comparison to petroleum-based surfactant was investigated through screening of enhanced oil recovery (EOR) methods including interfacial tension (IFT) measurement, aqueous stability, filterability ratio (FR), thermal stability, phase behavior, dynamic adsorption, and tertiary oil recovery test. These measurements were conducted in order to make a comparative analysis determining the best surfactant in the presence of high salinity brine (~ 16,000 mg/L) and reservoir temperature at 60 °C. The findings showed both of palm-oil based and petroleum-based surfactant were compatible with the high salinity brine. Additionally, the aqueous stability of palm-oil based surfactant did not indicate a clear solution while petroleum-based surfactant presented otherwise at room temperature and at 60 °C. The IFT measurement for both palm-oil based and petroleum-based surfactant demonstrated the optimum concentration 8000 mg/L with low IFT. In the next stage of FR test results, the palm-oil based surfactant had tendency to plug porous media as the value was above 1.2 while the petroleum-based surfactant met the criteria of FR <1.2 as the value was 1.04. The results of thermal stability test, the IFT value of the palm-oil based surfactant was decreasing while petroleum-based surfactant was relatively constant. In the phase behavior test, both of surfactant formed a Winsor type III. The result of the dynamic adsorption of palm-oil based surfactant did not show the lowest-standard limit of adsorption value < 400 µg/gr, but petroleum-based surfactant presented 358 µg/g. Surfactant flooding were conducted in rock core with permeability of 63 mD. The petroleum-based surfactant demonstrated an oil recovery factor (RF) of 54.2% OOIP. This current surfactant screening test indicated that the palm-oil based surfactant was
not well adapted to EOR methods. Overall, the main objective of this laboratory case study provides an evaluation of an alternative surfactant for EOR implementation in high salinity reservoir.