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 . Co_2 - 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