Effect of cationic and anionic surfactants on the wettability and interfacial tension of oil-brine systems in analogous rocks from the Chicontepec Paleochannel, Mexico

The chemical enhanced oil recovery (cEOR) uses substances to improve the mobility of petroleum in reservoirs. Among these substances are the surfactants, whose purpose is to change the wettability and interfacial tension (IFT). We focus on experiments of surfactants in rocks from Chicontepec Paleochannel. CTAB, DTAB and SDS surfactants in brines of NaCl and KCl and mineral oil were investigated for reduction of IFT and contact angle alteration. The sessile and pendant drop methods were used to determine the IFT. The electrical affinity of the rock surface, dissolved ions, and the surfactant molecules, play key roles in the alteration of wettability and IFT. Thus, one scheme of interactions between the electrical charges is proposed on the basis of the rocky characterization and the following results: the lowest contact angle was 106 degrees with CTAB at 0.01 wt% in brines at 9.25 g/L NaCl, and 108 degrees with SDS at 0.01 wt% in brines at 20 g/L NaCl. The smallest IFT was 0.813 dyn/cm with CTAB at 0.5 wt% in brines at 5 g/L KCl. This work serves as first assessments of these surfactants to enhance the production in Chicontepec, employing cheap tensoactives to increase the applicability. Besides, these results will guide future displacement tests as cEOR lab simulation.

Automated summary

Chemical enhanced oil recovery (cEOR) uses surfactants to improve the mobility of petroleum in reservoirs. In this study, experiments were conducted on CTAB, DTAB, and SDS surfactants in brines of NaCl and KCl and mineral oil to investigate their effects on interfacial tension (IFT) and contact angle. The results showed that the electrical affinity of the rock surface, dissolved ions, and surfactant molecules play important roles in altering wettability and IFT. These findings provide insights for enhancing production in Chicontepec and serve as a guide for future cEOR lab simulations.