Several parameters govern the oil displacement efficiency during microbial enhanced oil recovery (MEOR) processes. These parameters can be classified into four main parameters including (1) microbial growth, which is controlled by nutrient concentration and incubation conditions as well as the flooding sequence management, (2) bacteria community, (3) properties of porous media such as pore size and wettability and (4) other parameters. This paper presents the effects of these parameters on MEOR performance during two-phase flooding experiments in micromodels using reservoir fluid from a German high-salinity oil field. New micromodels generated based on μCT images of a Bentheimer core plug were used to investigate the MEOR displacement process under elevated pressure, temperature, and anaerobic and sterile conditions. As a result, it was found that microbial growth and its end-products have a significant role in the oil displacement efficiency during the MEOR process. Based on flooding experiments, a significant effect of bioplugging that improved the macroscopic conformance was observed during the MEOR process. This work gives new insights into the pore-scale mechanisms and factors affecting MEOR performance in porous media. The results presented in this paper could be used to support MEOR studies on a larger scale, such as those in the core plug or sandpack before field implementation.