EXPERIMENTAL EVALUATION OF SUPERCRITICAL CO2 ENHANCED OIL RECOVERY AND STORAGE CAPACITY USING DUAL-CORE CORE FLOODING TECHNOLOGY FOR CARBONATE RESERVOIRS

The depleted oil reservoirs are considered as the potential geological storage site for CO2, which is one of the solutions to carbon emissions and the increased temperature in the atmosphere. The geological properties of the depleted oil reservoir, such as reservoir heterogeneity, directly affect the amount of CO2 storage. Unfortunately, no research has been done on this topic. In this study, we experimentally studied the effect of reservoir heterogeneity on oil recovery factors in cases of seawater flooding and supercritical CO2 (sc-CO2) miscible injection and the resultant sc-CO2 storage in depleted oil reservoirs at the end of the oil field development. A dual-core flooding experiment involving two reservoir carbonate core samples with different permeabilities and porosities was carried out using live oil, which is that gas dissolves in the crude oil as the displaced phase. Seawater and sc-CO2 as the displacing phases were used to conduct water flooding and the miscible injection process under reservoir conditions (overburden pressure of 4,500 psi, pore pressure of 3,200 psi, and reservoir temperature of 102 degrees C), respectively. The scCO(2) miscible injection process was followed by seawater flooding to recover the remaining oil after seawater flooding and evaluate the storage capacity of sc-CO2. From the results of this study, it was found that sc-CO2 miscible injection following seawater flooding can recover additional oil, which is related to the properties of rocks. We also found that high-permeable rock has a significant potential for scCO(2) storage compared to low-permeable rocks. In addition, the effect of reservoir heterogeneity on the injectivity of sc-CO2, permeability loss, and scCO(2) storage efficiency is-also discussed.