Title : Comparative analysis of core flooding experiments and reservoir simulation results for chemical EOR methods in high viscosity oil reservoirs
Abstract:
High-viscosity oil reservoirs are commonly characterized by an unfavorable mobility ratio, early water breakthrough, and a large amount of residual oil after conventional waterflooding. Under these conditions, chemical enhanced oil recovery (EOR) methods require reliable laboratory validation and subsequent reservoir-scale assessment before field implementation. This study presents a comparative analysis of core-flooding experiments and reservoir simulation-based interpretation for chemical EOR methods aimed at improving oil recovery from high-viscosity oil reservoirs. The East Moldabek field in Kazakhstan is used as a representative case study.
The experimental part is based on core-flooding tests conducted on samples from Cretaceous and Jurassic productive horizons. The investigated chemical EOR methods include ASP flooding, polymer flooding, and surfactant solution injection, with conventional waterflooding used as the base case. The main evaluation indicators are displacement efficiency, incremental oil recovery after waterflooding, residual oil saturation, and changes in flow behavior associated with mobility control. The experimental results show that ASP flooding provides the strongest improvement among the tested chemical methods. In the Cretaceous core models, displacement efficiency increased from approximately 49% after waterflooding to more than 68% after ASP flooding, with an incremental increase of up to 19.2%. For the Jurassic core models, the increase was also significant, reaching up to 17.7%, depending on oil viscosity, permeability, and reagent formulation.
Reservoir simulation is considered as the necessary scaling stage for transferring laboratory-observed displacement mechanisms to field conditions. Core-scale results cannot be directly extrapolated to the reservoir without accounting for heterogeneity, well interaction, injectivity limitations, and sweep efficiency. Therefore, combining laboratory filtration data with reservoir simulation improves the technical justification of chemical EOR selection and reduces uncertainty in pilot design. The results confirm that chemical EOR, particularly ASP and polymer-based systems, is promising for high-viscosity oil reservoirs when mobility control and residual oil mobilization are the dominant recovery mechanisms.
