Experimental Investigation on the Availability of Yeast Cell Wall as anInterfacial Tension Reducer for Enhanced Oil Recovery

We studied on the availability of residue of squeezed beer yeast whose principal component is yeast cell wall for enhanced oil recovery as an interfacial tension reducer. The cell wall solution was hydrothermally treated in order to elute amphiphilic substances such as phospholipids, proteins, and fatty acids from the cell wall to the solution under different conditions such as concentration of the cell wall, temperature and time of the hydrothermal treatment, and salinity. The cell wall solution which was hydrothermally treated with crude oil was also applied to the measurement of interfacial tension between the solution and crude oil. The interfacial tension was reduced with decrease in salinity and increase in concentration of the cell wall and temperature of the hydrothermal treatment. The time of hydrothermal treatment didn't have much influence on the interfacial tension reduction. The capability of the cell wall solution which had been hydrothermally treated with crude oil to reduce the interfacial tension became larger than that of the cell wall solution which had been hydrothermally treated without crude oil. It was suggested that those interfacial tension reductions were brought by phospholipids and proteins eluted from the cell wall. Core flooding experiments were carried out by injecting the cell wall solution which had been hydrothermally treated with and without crude oil after the water flooding as the primary oil recovery. 2.0% and 1.2% of original oil in place was additionally recovered by injecting the cell wall solution which had been hydrothermally treated with and without crude oil respectively. These results support an advantage of process injecting the cell wall solution without hydrothermal treatment into high temperature oil reservoir. The injection of the cell wall solution can be a promising EOR which has both high cost performance and low environmental load.