An Experimental Study of Enhanced Foam Systems Used in High Temperature and High Salinity Bottom Water Reservoirs

Oil reservoirs that contain bottom water are abundant in China. However, the development of such reservoir is challenged by bottom water coning and ways of controlling it. Foam has the property of high apparent viscosity and high selective plugging ability, and it can have obvious pressure ridge effect in the development of bottom water reservoir. For the foams more effective, the better foaming agents SA, DR, AM were screened out through lab tests and by evaluating the foam composite index. Meanwhile, tests for compound of the foaming agents were conducted and four kinds of common foam system of high foam composite index were selected. In order to enhance the stability of common foam systems under the conditions of high temperature and high salinity, a polymer stabilizing foam agent was added and an enhanced foam system was formed. Under the simulated conditions of actual reservoir, aging tests were conducted for enhanced foam systems, for 7 days, 14 days, 21 days and 28 days. Finally, the enhanced foam system of 0.15%AM+0.05%DR+0.2%WP4 was selected for its better stability under high temperature and high salinity and applicability on rig site. The result of the flat model test showed that the pressure ridge effect of the enhanced foam system was better than the common foam system in high temperature and high salinity bottom water reservoirs, and improving the recovery rate apparently.