Quantitative Raman Spectroscopic Measurements of CO₂ Solubility in NaCl Solution from (273.15 to 473.15) K at p = (10.0, 20.0, 30.0, and 40.0) MPa

The knowledge of high pressure phase behavior of the CO 2 –H 2 O–NaCl system in a wide T – P – m NaCl range is of great interest in the injection of CO 2 to deep reservoir for storage or enhancement of oil recovery (EOR). The calculation of CO 2 solubility in brine is very important to predict the CO 2 storage capacity in saline aquifers. However, CO 2 solubility data at high salinity and high pressure are limited, and few thermodynamic models can accurately predict CO 2 solubility when salinity is higher than 4.5 mol/kg. In this study, a noninvasive technique, quantitative Raman spectroscopy, was used to investigate the high pressure equilibria of the CO 2 –H 2 O–NaCl system. A total of 180 solubility data points were obtained for carbon dioxide in (1, 3, and 5) mol/kg NaCl solutions from (273.15 to 473.15) K up to 40 MPa. New parameters were derived to improve the Duan-type solubility model, thus it can be applied in CO 2 sequestration and EOR to accurately calculate the solubility of CO 2 in NaCl aqueous solution up to 6 mol NaCl/kg H 2 O from (273 to 473) K, (3 to 60) MPa.