الملخص الإنجليزي
This study investigates the possibility to inject diluted aqueous solutions of novel surfactants into Yibal oil field (Sultanate of Oman) for EOR. Novel surfactants selected in this work were a series of amphoteric surfactants (SS30, SS880, SS882 and SS885). The experiment demonstrated the chemical compatibility of these surfactants with Yibal formation water. Critical micelle concentrations (CMCs) were found to be relatively low (0.002-0.003 W/v %) in Yibal reservoir conditions (temperature and salinity). This is a highly desired surfactant characteristic range in actual enhanced oil recovery application where the surfactant concentration should be above its CMC for effective performance, Furthermore, these surfactants generated relatively low equilibrium interfacial tensions (ITFs) between crude oil and surfactant solution. From CMC measurements, similar minimum surface area occupied by surfactant molecule (a = 52 Å?/molecule) was estimated. In addition, dynamic interfacial tension (DIT) between crude oil and brine were observed with all surfactants in the concentration range 0.05-0.5% (w/v%) in which the interfacial tension increase from an initial value (10--102 mNm-') much lower that the initial IFT in reservoir conditions (YRC - 20 mNm) to a higher equilibrium value depending on the surfactant type. This was taken as an indication for the occurring of a transient ultralow IFT. Finally, surfactant-crude oil-brine phase behavior in the concentration range 0.02-0.5%, generated gel-free oil-in-water microemulsions. This demonstrates the potential of these surfactants to generate alcohol free microemulsions.
