Generally, there are different enhanced oil recovery (EOR) methods. One of the most promising EOR method is the gas injection especially carbon dioxide (CO2) injection since it introduce several unique characteristic desired for higher tertiary oil recovery. In this study, the performance and feasibility of supercritical carbon dioxide (SC-CO2) and supercritical nitrogen (SC-N-2) injection to enhanced oil recovery was investigated. In this regard, swelling tests and core flooding experiments were performed to find out whether the injections of these gases are efficient to recover trapped oil in the reservoir. Based on the experimental results, the possible active mechanisms were discussed on both displacements. The results of swelling tests showed that SC-CO2 yields the swelling factor up to about 35%, while the oil swelling factor by SC-N-2 is just about 8%. The core-flooding experimental results demonstrated that SC-CO2 injection could recover 15.8% of the original oil in place (OOIP), while SC-N-2 injection ultimate oil recovery would be up to 8.7% of the OOIP. (C) 2016 Elsevier B.V. All rights reserved.