Experimental and numerical evaluation of the potential of improving oil recovery from shale plugs by nitrogen gas flooding

The potential of N2 flooding for improving oil recovery from shale core plugs has been demonstrated by the experimental observations and simulation results. Under a certain injection pressure, the results show that the oil was produced with a high and stable production rate at the initial period of the recovery process, before gas breakthrough. After that, the incremental RF decreased with the increase of a flooding period, and a much longer time had less effect on extracting more oil. We also examined the effect of injection pressure on gas breakthrough time, ultimate RF, and oil recovery history. This study illustrates that gas flooding could be considered as an improved oil recover (IOR) approach in shale oil reservoirs.