Improving Oil Recovery by Cold CO2 Injection: A Simulation Study

CO2 injection has been used for many years and it is accepted as a beneficial tertiary recovery method. However, there are very limited studies of liquid CO2 injection process and its effect on reservoir properties. The objective of this research is to investigate the effects of liquid CO2 injection on temperature distribution, fluid properties and oil recovery in a high temperature reservoir. A thermal compositional model is used to simulate the behavior of the reservoir in terms of viscosity, front movement and temperature. The main results of the study show that the temperature of the reservoir is affected by injection temperature and its rate; also, the effect of low temperature on viscosity cannot eliminate viscosity reduction by CO2. The recovery is doubled (12.81% increase) and mainly is due to liquid CO2 viscosity reduction by 6 times.