Dynamic Characterization of Viscous Fingering During Grading Viscosity Polymer Flooding (GVPF) in Heterogeneous Sandstone by Core-Scale Simulation

The primary objective of this research is to investigate the dynamic immiscible viscous fingering that occurs during grading viscosity polymer flooding in a heterogeneous core using simulations. The study also aims to assess the enhanced oil recovery (EOR) performance, including incremental oil recovery and the polymer utilization factor. Five bespoke core-flooding cases (full water flooding, full polymer flooding, polymer flooding followed by chase water, double-slug polymer flooding followed by chase water, and triple-slug polymer flooding followed by chase water) were conducted and analyzed to confirm the relationship between immiscible viscous fingering patterns and polymer EOR performance. This research has proven the potential of grading viscosity polymer flooding to improve oil recovery and delay water breakthrough with reduced polymer usage. The study also demonstrates the significance of accurately characterizing miscible viscous fingering to understand the performance of GVPF in core-flooding experiments and potential pilot implementation. This research contributes to selecting proper injection mode that can improve EOR performance while reducing polymer usage.