A Study On The Numerical Simulation Of Indigenous Microbes Enhancing Oil Recovery

In the light of the advantages and disadvantages in representative mathematical models at home and abroad, a new mathematical model was established based on two-step (aerobic/anaerobic) stimulating theory, microorganism reaction dynamic character and the mechanisms of indigenous microbe enhancing oil recovery (IMEOR). This mathematical model reflected the rules of variation of matter distribution caused by fluid flow and the cascade metabolic process of microbial communities. Additionally it accomplished the development from single porous flow field to coupled fields (porous flow field and microbial field), and described accurately and entirely the porous flow field and microbial field. This model has a theoretical basis for the research and development of the microbial flooding numerical simulation software.The partial differential equations could be translated into finite difference equations by scattering the time and space in the mathematical model for IMEOR. And the parameters of pressure and saturation in the model could be calculated by implicit and explicit expression respectively. Then the substitution of the coupled parameters such as water phase saturation, seepage speed and porosity in microbial field, the distribution of concentration about microorganism, nutriment and metabolites could be calculated implicitly. Based on the above procedures and calculations, the numerical simulation software for IMEOR was compiled, and it could accomplish the simulating calculation of the process of IMEOR basically and provide an effective simulation method for microbial enhanced oil recovery (MEOR). It is a milestone of the mathematical model development for MEOR.The researches of the IMEOR numerical simulation for the petroleum exploitation in oil field can establish a reasonable plan of the oil exploitation and determine the scientific working system, additionally reduce the operational risk in field tests of MEOR. For example, in a model of one dimention and two phases, the scheme designing of IMEOR was determined by simulating the indigenous microorganism two-step stimulating process with the software. Associating orthogonal test, the results of the numerical simulation showed that the optimized scheme is 1.5% (m/v) of the concentration of nutrient,0.1 PV of the injecting slug and 2 (m/m) of the concentration ratio of nutrient to oxygen. The predicted amount of enhanced oil could up to 2,029 t and the increased oil recovery is 8.46% under such project.