Evaluation of Microbial Enhanced Oil Recovery using the MRST Simulator

Abstract

Microbial enhanced oil recovery (MEOR), as a field of study, exploits the benefits of microbes for the purpose of improving microscopic as well as macroscopic displacement of oil by water. This work has been carried out to investigate certain mechanisms that affect the displacement process and limit the effectiveness of MEOR as an enhanced oil recovery technique. It was implemented via one-dimensional modelling and simulation of the MEOR displacement process with the MATLAB Reservoir Simulation Toolbox (MRST). By applying the dynamic modelling approach, mechanisms such as interfacial tension reduction by the action of biosurfactants, and component (bacteria and food) adsorption resulting in the formation of a biofilm have been studied. Simulation results generally revealed improved oil recovery compared to the base case of pure waterflooding. The effect of biosurfactants in mobilising residual oil in the reservoir has been found to result in the creation of a water saturation profile with two displacement fronts characterised by a travelling oil bank. Oil mobilisation commences much earlier when the combined effect of biofilm formation and IFT reduction by biosurfactants is active. The presence of indigenous microbes has been observed to limit the MEOR displacement process; however, this effect becomes less significant when high concentrations of exogenous bacteria are injected. Overall, MRST as a simulation tool has provided the necessary flexibility and robustness required for microbial EOR modelling making it suitable and recommendable for further modelling studies.