Session: 11-11-01 Advances in Carbon Capture Utilization and Storage

Paper Number: 80869

80869 - Correlation/Prediction of CO2 Solubility in Single-Salt and Multi-Salt Brines Using PR EOS Incorporated With Modified Alpha Functions and BIP Correlations 

Accurate prediction of CO₂ solubility in brine is of high significance for carbon capture, utilization, and storage (CCUS); however, no generalized methodology has been made available to successfully tackle such a technical challenge. In this study, a pragmatic and robust technique has been developed and generalized to correlate the CO₂ solubility in single-salt brine using the Peng-Robinson equation of state (PR EOS) together with  modified alpha functions and binary interaction parameter (BIP) correlations. A comprehensive CO₂ solubility database is firstly built to cover a large range of temperatures, pressures, salt concentrations, while five different salts are involved, i.e., NaCl, KCl, CaCl₂, MgCl₂, and Na₂SO₄. By integrating with the modified alpha functions and BIP correlations, such a generalized model is found to yield an average absolute relative deviation (AARD) of 5.24%, 5.82%, 7.64%, 6.04%, and 4.61% for the correlated CO₂ solubility in the aforementioned five single-salt brine, respectively. Compared with the existing correlations, the PR EOS-based model is better than the OLI, SP 2010, and DS 2006 models but only slightly inferior to the PSUCO₂ model under certain conditions. By combining a new BIP correlation, the newly proposed model has been extended to predict the CO₂ solubility in multi-salt brine with an AARD of 7.21%. In addition to its simplicity and high accuracy, this new model can not only be used to determine other physical properties including density, enthalpy, and surface tension of CO₂-brine systems, but also able to seamlessly integrate with any reservoir simulators, allowing for accurately evaluating and predicting performance of CO₂ enhanced oil recovery and storage capacity under various conditions.

Presenting Author: Zehua Chen China University of Petroleum (East China)

Authors:

Zehua Chen China University of Petroleum (East China)
Daoyong Yang University of Regina, Regina