More Residual Crude Oil Can Be Displaced Out by Micro-Forces in Chemical Flooding

Experimental results indicate that the displacement efficiency (De) after flooding by driving fluids with and without elastic characteristics is different at the same pressure gradient. Macro forces cannot explain the difference of the De by different driving fluids. Therefore, the changes of micro forces acting on residual oil by driving fluids with elastic properties and the increase in the De are analyzed. In this paper, through experimental analysis, the influence of elastic characteristics of the driving fluid on De is analyzed. The effects of change in micro forces on residual oil are analyzed. This micro force does not change the pressure gradient and mainly acts on the protruding portion of different types of residual oil, causing the protruding portion to change shape and mobilize or migrate. The results on visualization core models confirm the above calculation and analysis, the De after flooding by fluids with different elastic properties are given.