Numerical simulation for MEOR considering the size effect between microorganisms and porous media

Based on the analysis of size effect between microorganisms and porous media, a one-dimensional two-phase, five-component mathematical model was presented to simulate the process of microbial flooding. The components of this mathematical model consist of oil, water, microorganisms, nutrients and metabolites, wherein the main metabolite is biopolymer. The transport equations not only consider the characteristics of microbial growth, death, chemotaxis, convection-dispersion, and adsorption-desorption, but also consider the straining behavior and the behavior of products that cannot pass through all pore areas which are caused by the size effect of microorganisms and products. This newly developed model is validated with a classical simulator and a core flow experiment. In this study, the sensitivity of the straining coefficient and product inaccessible volume were analyzed through a simulator developed according to our mathematical model. We found that: (1) The straining deposition will be much larger than the adsorption deposition; (2) The straining behavior which is caused by the size effect of bacteria has a great influence on the microbial concentration and the oil recovery; (3) The product inaccessible volume caused by the size effect of product has a significant effect on the distribution of product concentration, but has little impact on the oil recovery.