2013 Volume 12 Issue 4 Pages 222-229
Carbon dioxide enhanced oil recovery (CO2-EOR) is a technique to recover the residual oil from oil reservoirs by injection of CO2. CO2 dissolution causes changes in the physical-chemical properties of oil, resulting in improvement in the oil recovery efficiency. However, the fundamental dissolution mechanism is not clear. To clarify it, we have investigated CO2 dissolution phenomena in cyclohexane (C6H12) using molecular dynamics simulations. The results show that CO2 dissolves in C6H12 by forming a cluster structure. The dissolution state of CO2 in C6H12 is discussed by comparing with the dissolution state of H2O in C6H12, and the electric fields around CO2, H2O, and C6H12 are analyzed from the viewpoint of molecular polarity and coulomb interactions. As a result, the CO2 dissolution state with cluster formation is considered to be strongly dominated by the similarity of the shape and size of the electric fields around CO2 and C6H12.