In this study, experimental conditions of the microbial enhanced oil recovery (MEOR) technique applied for Garzan oil (26° API; southeast Turkey) were utilized in a mathematical model that describes the transport of bacteria and its nutrients by convective and dispersive forces, including bacterial decay and growth. From the results of the variation of bacterial concentration with distance, it was observed that the bacterial concentration increased as the nutrients were consumed with time. Although some bacteria died during the experiments, this did not slow down the overall increase in bacterial population significantly at earlier times. However, in the later periods of the soaking process, severe bacterial decay occurred due to the lack of nutrients. The pressure behavior in the model during the shut-in period was also calculated and agreed well with the experimental results.