CO₂ Sequestration/EOR in Bartlesville Sandstone Reservoir Bearing Heavy Oil

In order to reduce the anthropogenic greenhouse-gas emissions, CO₂ geological storage has been proposed. Many applications for CO₂ geological storage exist, such as injecting CO₂ into depleted hydrocarbon reservoirs, enhanced coalbed methane recovery, and enhanced oil recovery (EOR) operations. CO₂ injection has been extensively studied by many researchers and has resulted in large oil recoveries. Injecting CO₂ alone experienced an early breakthrough problem, which is unfavorable in CO₂ sequestration projects. CO₂ must be kept inside the oil reservoir. This pushes researchers to combine water with CO₂ flooding to improve the sweep efficiency. In this study, we investigated the effect of water salinity on CO₂ flooding and on the water–rock interactions during WAG. The results of this study show that combining LS water with CO₂ flooding prevents early breakthrough by improving CO₂ sweep efficiency. The oil recovery was also high due to merging LS water with CO₂ flooding. Controlling the injected water chemistry has a large influence on both oil recovery and CO₂ solubility in crude oil. The highest effect of added chemicals can be ranked in an order of NaCl> CaCl₂> Mixed NaCl, CaCl₂, and MgCl₂>MgCl₂.