Design and evaluation of enhanced oil recovery using polymer flooding techniques

Thesis Abstract

Enhanced oil recovery (EOR) methods are critical for maximizing hydrocarbon extraction from mature reservoirs, yet many techniques remain under-optimized in terms of design and implementation, particularly those involving polymer flooding. The persistent challenge lies in effectively improving sweep efficiency while minimizing operational costs and environmental impacts. This study aims to design a tailored polymer flooding protocol and evaluate its effectiveness in enhancing oil recovery from a North American sandstone reservoir. The primary objectives are to develop a comprehensive polymer formulation suited for the reservoir’s pore structure, simulate polymer flow behavior under reservoir conditions, and empirically assess the recovery efficiency through laboratory core flooding experiments. The research adopts a mixed-methods approach, combining quantitative simulation and experimental procedures. The population comprises core samples obtained from the reservoir, with a total of 30 core plugs representing diverse porosity and permeability ranges. The sample size was determined based on statistical power analysis to detect significant differences in recovery efficiency with an alpha level of 0.05 and a power of 0.8. Data collection involved laboratory core flooding experiments, rheological characterization of polymer solutions, and reservoir simulation modeling. Rheological properties were measured using a rotational rheometer to analyze viscosity profiles across varying shear rates, ensuring the polymer formulation’s stability and injectivity. The experimental phase involved injecting polymer solutions at different concentrations (1000, 2000, and 3000 ppm) into core samples, with flow rates maintained consistently to monitor pressure differentials and oil displacement. Data on volumetric displacement, pressure drop, and recovery factors were collected and analyzed using ANOVA to assess the significance of polymer concentration on recovery efficiency. Complementarily, a numerical reservoir simulation employing Eclipse simulation software integrated laboratory-derived parameters to model polymer flow behavior under in-situ conditions, allowing optimization of injection schemes and prediction of field-scale performance. Key findings are anticipated to reveal that polymer solutions with a concentration of approximately 2000 ppm achieve optimal viscosity and mobility control, leading to a significant increase in oil recovery—expected to reach an additional 15–20% of residual oil. The results are expected to demonstrate that tailored polymer formulations enhance sweep efficiency by reducing fingering and channeling phenomena, in alignment with theories of wettability and flow heterogeneity from the literature. The simulation model is projected to validate the laboratory results, indicating that polymer flooding significantly improves volumetric displacement and recovery factors compared to waterflooding alone. This study contributes to the existing body of knowledge by providing a systematic framework for designing and evaluating polymer flooding protocols specific to sandstone reservoirs, integrating laboratory experimentation with predictive modeling. The findings offer practical guidelines for optimizing polymer properties and injection strategies, ultimately facilitating more efficient design of field-scale polymer EOR projects. The research underscores the importance of reservoir characterization, rheological assessment, and simulation integration in advancing polymer flooding technology. The main conclusions emphasize that carefully formulated polymer solutions can substantially enhance oil recovery, with economic assessments indicating improved project viability at optimized concentrations. It is recommended that operational parameters be refined based on laboratory and simulation results before field implementation. Additionally, future research should explore polymer biodegradability, environmentally friendly formulations, and the effects of reservoir heterogeneity on performance. Overall, this study advances both theoretical understanding and practical application, bridging laboratory insights with field-scale EOR design to promote sustainable hydrocarbon production.