A visualized physical model was designed according to the similarity theory. The remaining oil development effects of nitrogen gas injection and nitrogen foam injection after bottom water driving were studied comparatively and EOR mechanisms for nitrogen foam flooding was analyzed through physical simulation. Experimental results illustrate that the remaining oil exists as the“attic oil”after bottom water driving. Both the nitrogen gas injection and nitrogen foam injection can displace remaining oil effectively. However,the foam flooding can enhance sweep efficiency through the effect of mobility control and plugging, adding that foam has a higher displacement efficiency in swept region, which leads to a higher ultimate recovery than gas injection. The experiments show a possible way to tap remaining oil and enhance oil recovery for the carbonate fracture-vuggy reservoir after bottom water driving.