The application discloses a CO2-
ion water flooding molecular dynamics simulation method and belongs to the technical field of CO2
oil displacement. The method comprises the following steps: establishing oil molecule models, water molecule models, CO2 molecule models, CaCl2 molecule models and
graphene plate models corresponding to the characteristics of a target oil reservoir; optimizing the geometric structures of the models; assembling the optimized molecular models into a CO2-CaCl2-H2O ternary displacement
system and performing
molecular dynamics simulation; selecting an NVT ensemble during
simulation, applying a periodic boundary condition, adopting a
COMPASS II force field and configuring atomic potential parameters, running
energy minimization and temperature initialization, and then performing displacement
process simulation; quantitatively evaluating the
oil displacement effect of the displacement medium of the CO2-CaCl2-H2O ternary
system based on a trajectory file output by simulation; and the application can better explain the behavior of molecules under the synergistic action of multiple displacement media, reflect the
oil displacement microscopic mechanism under the synergistic action of multiple displacement media, and has important significance for optimizing the development effect of
tight oil reservoirs and improving the
recovery rate.