COMPARATIVE ANALYSIS: CO2 INJECTION FOR HEAVY OIL RECOVERY IN SANDSTONE AND SHALY SAND RESERVOIRS

ABSTRACT

This study employs computational simulations from the CMG software to comprehensively evaluate the impact of Continuous CO2 Injection (CCI) rate on heavy oil recovery in geologically intricate reservoirs. The modeling includes 3D representations of shaly sand and sandstone formations, with CCI simulations conducted at varying rates (1-4 million ft3 /day) for each scenario. The primary metrics examined are Oil Recovery Factor (RF), CO2 displacement efficiency, and production rate. The analysis compares the performance of these metrics across different CCI rates and reservoir types to determine the most effective model for successful CO2 injection initiatives. The provided report encompasses simulation outcomes, KPI evaluations, assessments of heterogeneity impact, recommendations for optimal model selection, and suggestions for future research avenues, including field pilot studies for validation. It is crucial to emphasize that this investigation is entirely based on simulations and excludes experimental work or field data analysis. Interestingly, in the less porous shaly sand model, CO2 demonstrated higher velocity attributed to its constrained storage capacity, resulting in quicker CO2 breakthrough potentially bypassing substantial oil reserves. Conversely, the more porous sandstone model exhibited slower initial CO2 displacement while achieving a more consistent sweep due to its larger pore volume and flow pathways, potentially leading to increased overall recovery. The limitations of the shaly sand model in handling higher injection rates (pressure buildup) were revealed as a critical constraint. Effective CO2 injection typically necessitates adequate volumes for efficient reservoir sweep.