POSSIBLE STORAGE OF CO₂ IN SALINE AQUIFER: STORAGE FACTOR ESTIMATION

The objective of this study is to perform laboratory measurements and a CO₂ underground storage study to cover the knowledge gap on CO₂-Brine relative permeability and assess various variables on the storage of CO₂ in a selected aquifer. Several factors that affect CO₂ storage have been discussed in the literature. These include both macroscopic and microscopic displacement efficiency of brine as a function of CO₂ pore volume injected. It is clear from the literature that there is still more work needed to investigate the effect of various variables such as formation temperature, brine viscosity, and the possible presence of free gas in the aquifer on the CO₂ storage efficiency of the selected aquifer. Experimental tests were conducted on four carbonate-limestone core samples to determine the capillary pressure curves and to conduct CO₂ flooding into 100% brine saturated core samples. Each core sample has with different brine salinity. Flooding tests were conducted at constant injection pressure yet, the injection temperature for each core sample was different. The brooks-Corey correlation was used to obtain the relative permeability curves of the CO₂ -Brine system. Using experimental results of capillary pressure, a modified Ritter and Drake correlation was used to determine the pore throat size distribution. This thesis research shows the results of limestone core flooding tests and CO₂ flooding of an aquifer runs obtained using Petroleum Solution software to evaluate the effect of brine viscosity, temperature, and gas saturation on aquifer CO₂ storage capacity (storage factor). The results revealed that the CO₂ storage capacity increases as temperature increases because of thermal effects. Whereas, as the gas saturation increases, the storage capacity of the selected zone decreases. In addition to that, the flooding runs showed that relatively high viscosity of brine aquifer hider the CO₂ storage capacity of the reservoir