Experimental and Numerical Analysis of Selective Plugging during Microbial Enhanced Oil Recovery in a Glass Micromodel

Selective plugging is one of the most effective mechanisms in microbial and chemical enhanced oil recoveries. In the experimental section, the water solution of purified Acinetobacter sp. and distilled water were injected to an oil saturated heterogeneous micromodel porous media. The main goal of this experiment was to examine the effect of water-bacteria cell solution in the water flooding performance and to compare it with pure water flooding. Pure water injection could expel oil by 41% while the bacterial solution injection was resulted in higher oil recovery, i.e. 7% improvement. In the simulation section, a heterogeneous geometry was used as porous media. To obtain water and oil distribution, Navier-Stokes equations were solved in time-dependent mode. Computational domain was discretised using triangular meshes. Moreover, the mesh independency analysis showed that the results are not dependent to the size of meshes. Seven different models were constructed to evaluate the influences of selective plugging in our porous media’s throats and routes during this process; moreover, the results illustrated that pour size fluid distribution is strongly related to the plugging distribution. After plugging of main diameter, wetting fluid inevitably exits from sidelong routes located in top and bottom of the matrix. It was shown in each model that the oil recovery was increased after throats, and routes were plugged in comparison with no plug model. Models no. 2, 4, and 6 had almost the same recovery while fluid distribution was different. The obtained results showed that Cahn-Hilliard phase field method can accurately predict water-oil displacement on pore scale under the selective plugging mechanism.