Quantitation of microbial products and their effectiveness in enhanced oil recovery. Final report

摘要

A three-dimensional, three-phase, multiple-component numerical simulator was developed to investigate transport and growth of microorganisms in porous media and the impacts of microbial activities on oil recovery. The microbial activities modeled in this study included: (1) growth, retention, chemotaxis, and end product inhibition of growth, (2) the formation of metabolic products, and (3) the consumption of nutrients. Major mechanisms for microbial enhanced oil recovery (MEOR) processes were modeled as follows: (1) improvement in sweep efficiency of a displacement process due to in situ plugging of highly-permeable production zones by cell mass or due to improved mobility control achieved by increasing the viscosity of the displacing fluid with a biopolymer, and (2) solubilization and mobilization of residual oil in porous media due to the reduction of the interfacial tension between oleic and aqueous phases by the production of a biosurfactant. The numerical solutions for mathematical models involved two steps. The distributions of pressure and phase saturations were solved from continuity equations and Darcy flow velocities for the aqueous phase were computed. This was followed by the solution of convection-dispersion equations for individual components. Numerical solutions from the proposed model were compared to results obtained from analytical equations, commercial simulators, and laboratory experiments. The comparison indicated that the model accurately quantified microbial transport and metabolism in porous media, and predicted additional crude oil recovery due to microbial processes. 50 refs., 41 figs., 26 tabs.