Mathematical Modeling of Microbial Enhanced Oil Recovery

ABSTRACT Microbial enhanced oil recovery (MEOR) is receiving renewed interest worldwide. Microbial enhanced oil recovery involves the injection and transportation of microorganisms into the reservoir followed by nutrients which act as in situ growth products. These bacteria act as either a mobilizing agent of residual oil or a plugging agent for selective plugging of an undesired reservoir zone. Even though the concept of MEOR activities is rather straight forward, field tests have often been dismal. One of the reasons for such failure has been reported to be the inability to set up proper field strategy. In order to develop a proper strategy, a reservoir simulator capable of predicting bacterial movement and reactions in an oil reservoir. Such a simulator has been nonexistent to-date. This paper presents formulation and results of reservoir simulation using microbial EOR. The formulation developed in this paper describes microbial transport in multidimensional porous medium. This description is completed with a kinetic model of bacterial growth which leads to either bacterial plugging and mobility control or alteration of oil properties (reduction of oil viscosity, interfacial tension (IFT), etc.). Reservoir simulation results are given for different types of bacteria used. A Canadian heavy oil reservoir was used as the prototype for all numerical simulation results.