Chemical flooding of oil reservoirs .4. Effects of temperature and pressure on the middle phase solubilization parameters close to optimum flood conditions

The effect of pressure and temperature on the multi-phase behavior of a multicomponent model oil, with and without methane, and a one-component surfactant system has been studied al constant salinity (2.20 wt.% NaCl solution) close to the optimum condition for oil recovery. Solubilization parameters of oil and water in the middle phase have been determined at actual temperatures (70-110 degrees C) and pressures (100-600 bar). Both of the systems showed a normal phase behavior in the three-phase region by changing the pressure and temperature. Increase in pressure and temperature caused the systems to move towards the II(-) state. The variation in the solubilization parameters caused by changes in pressure and temperature close to optimum flood condition is discussed. The multiphase behavior is also discussed in relation to the composition of the oil.