Reaction kinetics model and numerical simulation method of microbial flooding in oil reservoirs

Key words:  microbial flooding  numerical simulation  reaction kinetic model  sensitivity analysis  enhanced oil recovery

Abstract:

A reaction kinetics model for microbial flooding was established, which can be used in reservoir numerical simulation, and the calculation method of the key parameters in the reaction model and the characterization method for the important enhanced oil recovery mechanisms were proposed, including viscosity reduction of crude oil, viscosity increase of formation water and change of oil-water interfacial tension. Then a conceptual microbial flooding model was established based on the reservoir data of a pilot test in Shengli Oilfield. Sensitivity analysis of different microbial flooding parameters was carried out, and the oil displacement performance of the microbial flooding process were analyzed accordingly. The results show that the higher the degree of the microbial degradation of crude oil, the higher the degree of the viscosity increase of formation water, the higher the enhanced oil recovery (EOR).There is a critical value of the initial microbial concentration in the reservoir to achieve good EOR performance. There is also an optimal value for the degree of surface tension reduction by microorganisms, and extremely high or low value is not conducive to the performance of microbial oil displacement. The proposed reaction kinetics model and numerical simulation method of reservoir microbial flooding can reasonably describe and characterize the growth and metabolic process of the microbial sand the key mechanisms of the microbial flooding, which can provide a reliable theoretical basis for the implementation of the microbial EOR method.