Design and optimization of phosphate-containing alkaline flooding formulations.

摘要

The effects of divalent ions on the interfacial tension (IFT) behavior of optimized formulations that include phosphate ions, and the effects of several parameters on surfactant adsorption and transport through porous media are the topics of this report. The phase behavior and interfacial activity of mixtures containing sodium phosphate, sodium carbonate, sodium bicarbonate, surfactant, and crude oils were studied at three pH levels in order to identify combinations that produce interfacial activity. Three crude oils with total acid numbers (TAN) that range from very low to moderate were tested. Optimal salinities were found for producing the best interfacial activity with all three crude oils and the phosphate-containing surfactant-enhanced alkaline chemical system, and low levels of calcium ions had no detrimental effect on the IFT behavior. Coreflood experiments were performed with an anionic surfactant that is designed for use in EOR applications. 15 refs., 29 figs., 6 tabs.