Interfacial tension and contact angle measurements for the evaluation of CO₂‐brine two‐phase flow characteristics in porous media

Abstract

It is of great importance to investigate gas and water flow characteristics to better understand the geological CO2 sequestration process. The interfacial tension between CO2 and brine and the wettability of reservoir rocks are the most important parameters for two‐phase flow in porous media that have a significant influence on the capacity of CO2 storage. In this paper, we present a set of interfacial tension data between CO2 and a sodium chloride (NaCl) solution and the contact angle data between CO2, NaCl and quartz by using a visual experimental method at multiple pressure, temperature and salinity conditions. We also performed simulations of CO2 and NaCl solution two‐phase flow in quartz bead‐packed beds by introducing interfacial tension and contact angle data into the pore network model to evaluate the relative permeability and capillary pressure. We found that the phase alternation of CO2 from a gas to its supercritical state has a significant influence on the wettability of pore surfaces and thus governs the capillary trapping mechanism. This indicates that CO2 sequestration efficiency in a saline aquifer will be greatly affected while CO2 is in its different phase states. The simulation results showed that a pore network model is available for the study of CO2 and brine two‐phase flow characteristics in porous media. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1756–1762, 2015

Measurement and modelling of interfacial tension in methane/water and methane/brine systems at reservoir conditions

“…Similar to other gas-water systems [5,8,[10][11][12][13][14][15][16][17][18][19], the addition of salt resulted in a general increase of the interfacial tension values over the pressures and temperatures considered, as depicted in Figure 8. Overall, the presence of 5 wt% and 10 wt% NaCl resulted in an average increase of the IFT in 1.4 mN.m -1 and 4.1 mN.m -1 , respectively, when compared to the methanewater IFT.…”

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

“…Figure shows the deviations Δγ (mN·m −1 ) of the interfacial tension using empirical equations under the same conditions as that used for the experiment. The empirical equation was also used to fit our previous data . The plot shows that the deviations ranged from −4 to +4 mN·m −1 .…”

“…The pendant‐drop experimental apparatus is shown in Fig. ; it has been described in detail in our previous work . The measuring system mainly consists of a pressure vessel with two windows, pressure control pump, temperature controller, image capture camera, and data acquisition and processing computer.…”

“…The interfacial tension between CO 2 and pure water systems was mainly measured at pressures and temperatures ranging from 0.1 to 20 MPa and 5°C to 62°C . Later, NaCl solutions with different salinities were used for interfacial tension measurements for temperatures ranging from 298 K to 423 K and pressures up to 69.51Mpa, and salt molalities up to 4.28 mol·kg −1 . All authors reported that the interfacial tension of the CO 2 –brine system increases with temperature and salinity and decreases with pressure until it asymptotically reaches a pseudo‐plateau value.…”

“…[9][10][11] Later, NaCl solutions with different salinities were used for interfacial tension measurements for temperatures ranging from 298 K to 423 K and pressures up to 69.51Mpa, and salt molalities up to 4.28 mol·kg −1 . 5,8,[12][13][14][15][16][17][18][19] All authors reported that the interfacial tension of the CO 2 -brine system increases with temperature and salinity and decreases with pressure until it asymptotically reaches a pseudo-plateau value. However, doubt remains about the accuracy of interfacial tension data based on the different experimental methods used to determine the thermodynamic equilibrium.…”