Core Flooding Experiments on the Impact of CO₂-EOR on the Petrophysical Properties and Oil Recovery Parameters of Reservoir Sandstones in Kazakhstan

Abstract

This study investigates the impact of CO2-enhanced oil recovery (CO2-EOR) on the petrophysical properties and oil recovery potential of sandstone reservoirs in the oilfields located in the east-southern Precaspian region of Kazakhstan. Despite the recognized potential of CO2-EOR for improving oil recovery and aiding carbon sequestration, there is limited understanding of how CO2-EOR specifically affects the petrophysical properties of sandstone reservoirs in this region. Laboratory experiments were conducted using two core samples from the selected oilfields to examine changes in porosity, permeability, and oil recovery coefficients. The results demonstrated that porosity changes ranged from a slight increase of 1.1% to a decrease of 1.5%, while permeability reduction was significant, with decreases ranging from 29% to 50% due to clay alteration and halite precipitation. The oil recovery coefficient after CO2 flooding was found to be between 0.49 and 0.54. These findings underscore the complex interactions between CO2 and reservoir rocks, emphasizing the need for tailored EOR strategies in different geological settings.

Keywords

• CO₂-EOR
• sandstone
• enhanced oil recovery
• core sample
• petroleum oilfields
• pore network distribution