Effects of Na⁺, K⁺, Ca²⁺, and Mg²⁺ cations on CO₂–brine interfacial tension under offshore storage conditions

Abstract

The laboratory determination of CO2‐brine interfacial tension is very important for estimating the storage capacity of saline aquifers during the CO2 sequestration process. In this paper, we measured CO2 and the brine interfacial tension using the pendant‐drop method at a temperature of 285–300 K and pressure of 3–9 MPa. The brine was composed of Na+, K+, Ca2+, and Mg2+ cations with different molalities. The experimental results indicate that interfacial tension increased with temperature and salinity but decreased with pressure until it reached a plateau. At the same temperature and pressure, the plateau value increased with increasing brine salinity for all types of brines used in this work. Moreover, the plateau exists whenever the CO2 is liquid. The interfacial tension between CO2 and brine with bivalent cations is larger than that between CO2 and monovalent brines. Finally, we established an empirical equation based on the relationship between interfacial tension and temperature, pressure, and salt molality grounded on experimental data, which allows the evaluation of CO2–brine interfacial tension values with a mean deviation of ±4 mN·m−1. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.

Synergies of storing hydrogen at the crest of CO2${\rm CO}_{2}$ or other gas storage

“…54 Brine/H 2 IFTs lie in the range of ≈50-75 mN/m, [53][54][55][56][57][58] whereas under similar T , P, and brine salinity, brine/CO 2 IFTs are about twice smaller, in the range of ≈20-35 mN/m. 49,59,60 Brine/CH 4 and brine/N 2 IFTs have values intermediate between brine/CO 2 IFTs and brine/H 2 IFTs, the latter being slightly smaller than the former. 61,62 Correlations and simple models are available for brine-H 2 IFTs 54,55 and brine-CO 2 IFTs 63,64 as a function of T , P, and brine salinity (see also the recent critical review by Mouallem et al 65 ).…”

“…Subsequent studies have been concerned with only a subset of those gases and/or have gathered and examined IFTs from various sources 54 . Brine/$${\rm H}_2$$ IFTs lie in the range of $$\approx$$50–75 mN/m, 53–58 whereas under similar $$T$$, $$P$$, and brine salinity, brine/$${\rm CO}_2$$ IFTs are about twice smaller, in the range of $$\approx$$20–35 mN/m 49,59,60 . Brine/$${\rm CH}_4$$ and brine/$${\rm N}_2$$ IFTs have values intermediate between brine/$${\rm CO}_2$$ IFTs and brine/$${\rm H}_2$$ IFTs, the latter being slightly smaller than the former 61,62 .…”

Toward Predicting Interfacial Tension of Impure and Pure CO2-Brine Systems Using Robust Correlative Approaches

“…In order to model the IFT of both impure and pure CO 2 -brine systems, 2811 experimental data points were gathered from reliable literature sources. − ,,,− This database is the most comprehensive collected for the IFT of CO 2 -brine to date, containing about 290 or more data from similar studies. Typically, in these investigations, impure brine is synthesized through the introduction of salts such as KCl, NaCl, CaCl 2 , Na 2 SO 4 , and MgCl 2 .…”

A Supervised Learning Approach for Accurate Modeling of CO2–Brine Interfacial Tension with Application in Identifying the Optimum Sequestration Depth in Saline Aquifers

“…To date, extensive laboratory tests have been conducted to investigate the pure and impure CO 2 –brine IFT characteristics subject to varying pressures, temperatures, salt types, and brine molalities − These laboratory tests were completed using either the pendent drop method or the capillary rising method, both of which require careful calibration of the high-pressure experimental apparatus, time-consuming operation procedure, and complicated data deduction technique. Besides, discrepancies may exist in the interpreted IFT data at analogous conditions, which may be attributed to uncertainties stemming from operations and data deductions .…”