Densities for Ternary System of CaCl2–H2O–CO2 at Elevated P-T: An Experimental and Modeling Approach

Abstract

Very few thermodynamic models exist for estimation of density alteration due to solution of CO2 in a pure H2O and CaCl2–H2O system. All of these models require density of CaCl2 solution to estimate density of CaCl2–H2O–CO2 system. Similarly, models presented to calculate CaCl2 solution density need pure H2O density in advance. The main approach to model density of CaCl2–H2O–CO2 system is based on estimation of density alteration of CaCl2–H2O system due to the solution of CO2 mole fraction. Hence, to estimate CO2–CaCl2–H2O system density, density of CaCl2 solution is necessary, and to estimate density of CaCl2–H2O system, density of pure H2O is required in advance. Firstly in this paper, density of 0, 1.91, and 4.85 mol/kg CaCl2 solutions saturated with CO2 at 328.15 to 375.15 °K and 68.9 to 206.8 Bar were measured through laboratory experiments. Then, a new model is developed to estimate the density of CaCl2 solutions containing CO2 based on the experiments conducted in this study. The average and maximum absolute deviations of the new model from the experimental data are 0.0047 and 0.0177, respectively. Hence, the new model combined with other existing models to separately calculate density of the CaCl2 solution can be used to accurately predict density of the CaCl2–H2O–CO2 system in a wide range of P-T applicable for subsurface reservoirs.

Effect of produced carbon dioxide on multiphase fluid flow modeling of carbonate acidizing

“…A relation proposed by Bastami and Pourafshary (2018) was used to estimate the density of the aqueous solution of calcium chloride containing CO 2 aq , as shown in Eq. 26.…”

“…Bastami and Pourafshary (2016) developed a continuum model considering the acid consumption and the effect of reaction products, such as free gas, on the acid flow and the wormhole propagation. Bastami et al (2018) extended this work by considering a thermodynamic model to calculate the density of the H 2 O-CaCl 2 -CO 2 system. Cheng et al (2017) performed core flooding experiments and CT scan observations to investigate the effect of carbon dioxide at different temperatures and pressures on wormhole behavior.…”