Mehdi ForoozanfaR - Petroleum Engineering Department , Kish International Campus ,University Of Tehran , IRAN

Considerable volume of the reservoir oil are left-behind at the end of primary depletion and later oil recovery methods. Employing the proper EOR methods can maximize oil recovery from the target reservoir . Each of the recovery process is associated with the various fundamental theories and mechanisms. Enhanced oil recovery methods are all the technique of recovering crude oil , condensate or natural gas liquids that requires the utilization of energy and/or materials . Co2 - assisted gravity drainage EOR process is a top-down process in which gas is injected in the gas-cap through vertical or horizontal wells at a rate lower than the critical rate . In this research two sensitivity analysis done first grid block size in X and Z direction and the second is numerical method , increasing the grid block size in X direction has a positive impact on oil recovery and for Z direction is vice versa .

Gravity Drainage , Grid Block Size , Numerical Method