Microbial Enhanced Oil Recovery - Modeling and Numerical Simulations

Abstract

This thesis examines the process by which microbes are used to enhance oil recovery from subsurface reservoirs. A brief introduction to reservoirs is given and the possible effects of microbes are explained. A model is developed combining porous media flow and microbial kinetics. The model is then used to run simulations in conjunction with the MATLAB Reservoir Simulation Toolbox from SINTEF (Stiftelsen for Industriell og Teknisk Forskning). Microbial enhanced oil recovery (MEOR) is simulated by injecting a microbe and nutrient mix into the reservoir. The microbes consume the nutrients and then reproduce and create metabolites according to the Monod model of bacteria. The metabolites are simulated to be either surfactant or polymer which are both beneficial to oil recovery. Surfactant reduces the residual oil level while polymer increases the volumetric sweep of the reservoir. Langmuir equilibrium adsorption is used to model the formation of biofilm. This results in more metabolites being produced nearer the injection sites. An attempt to recreate the results of Nielsen et al. (2010) and Lacerda et al. (2012) is made. Differences in the results are highlighted and explained. Further testing is done to examine the impact of a high permeability thief zone to the model. The thesis concludes that the model and its implementation have been successful so far though more testing should be done.