Reducing Adsorption of a Gemini Surfactant on Carbonate Rocks Using Low Salinity Water

Abstract

Surfactants are widely employed in chemical enhanced oil recovery (cEOR) technique. The economics of a cEOR project is directly impacted by the amount of surfactant loss caused by adsorption on a rock. Therefore, surfactant adsorption reduction is imperative. Both static and dynamic adsorption experiments were conducted to test the adsorption reduction of a novel Gemini surfactant on Indiana limestone. This novel surfactant is tolerant to high-salinity and high-temperature environments. Low salinity water was made by diluting sea water ten times. The salinity of Low salinity water was 6771 ppm. Rock characterization was performed first using XRD. Static adsorption tests were run using a crushed rock sample. Whereas core flood experiments were conducted to determine the dynamic adsorption behavior. High-performance liquid chromatography integrated with an evaporative light scattering detector was employed to calculate the unknown concentration of the surfactant. The effect of both high and low salinity water along with Gemini surfactant was investigated on the static adsorption of Gemini surfactant on Indiana limestone. It was shown that high salinity conditions result in the adsorption reduction in comparison with Gemini surfactant in deionized water. However, the use of low salinity water in the aqueous solution of Gemini surfactant further results in reducing surfactant adsorption. Dynamic adsorption test on Indiana limestone was found consistent with static tests. The ultimate reduced adsorption value of Gemini surfactant on Indiana limestone was found to be 0.11 mg/g-rock using low salinity conditions in dynamic experiments. Such low value lies under the economic limit, making a chemical EOR process efficient and economical. The novelty of this work is the use of low-salinity water in reducing the adsorption of a Gemini surfactant on Indiana limestone. The use of such a technique helps industrialists and researchers in designing an efficient and economical chemical EOR process.