Polymer flooding characteristics in modified Hele–Shaw cells

In this study, numerical simulations are employed to investigate the displacement flow of oil by viscoelastic polymer solutions inside modified Hele–Shaw cells (HSCs). The flooding characteristics within converging and diverging geometrical configurations and various flow injection rates are explored by utilizing the White–Metzner model to capture the viscoelastic behavior of hydrolyzed polyacrylamide solutions at different concentrations. The simulations are conducted in OpenFOAM using the volume of fluid method to model the multiphase interface. Results demonstrate that higher elasticity numbers (El) and lower modified capillary numbers (Ca′) enhance the oil recovery to over 75% in terms of swept volume due to improved flow stability and reduced finger branching. Additionally, the diverging HSCs positively influence the flow patterns and facilitate an extra increase in sweeping efficiency (SE) by more than 12% via favorably alleviating the stability threshold in terms of Ca′–El relationship. In contrast, the opposite holds for the converging channel, decreasing SE by 16% and narrowing down the stability region. The findings indicate that adjusting polymer concentration and cell configuration can mitigate the adverse effects of finger instability, thereby improving the overall success of oil displacement processes. Moreover, a supervised machine learning study was carried out to predict the sweep efficiency based on the flow dimensionless numbers, where the multi-layered artificial neural network was exhibited as a high-accuracy model with an R2 value of 94.46%.