Determining of fluid injection shear rate into the near wellbore region through the Computational Fluid Dynamics simulation

Among various factors affecting the stability of the emulsion, shear rate is crucial as the energy supply for emulsification. Nonetheless, the shear rate applied by fluid injection into the porous medium of the crude oil reservoirs is unknown and requires further investigation due to the complexity of fluid flow in the porous region and the interaction of immiscible fluids. In this study, the shear rate behavior of two-phase flow in the pore scale has been analyzed to investigate the impact of various factors including water injection rate, oil viscosity, wateroil interfacial tension, and wettability. A two-dimensional model incorporating the Cahn-Hilliard phase-field and Navier-Stokes equations was developed and solved using the finite element method. According to the results, the shear rate in the pore body and pore throat varied between 1 and 660 s-1, mostly ranging from 100 to 150 s- 1 The shear rate increased with the injection rate and decreased with oil viscosity. Increasing the water injection rate from 0.032 to 0.077 cm/s raised the shear rate up to threefold, while wettability alteration from the waterwet to the oil-wet conditions enhanced it by 1.92 times. To simulate real field conditions in the laboratory tests, the equivalent mixer rotation speed was calculated between 10 and 6300 rpm, however, the optimal laboratory speed was determined to be 1000 to 1500 rpm for the dominant shear rates (100 to 150 s- 1). As a result, the shear rate, the parameters influencing it, and the equivalent mixer rotation speed were determined.