Interfacial Tensions between Reservoir Brine and CO₂ at High Pressures for Different Salinity

Abstract

In this paper, an experimental technique has been developed to study the interfacial interactions of the reservoir brine and CO2 system at high pressures and elevated temperatures. Using the axisymmetric drop shape analysis (ADSA) for the pendant drop case, this new technique makes it possible to determine the interfacial tension (IFT) and visualize the interfacial interactions phenomenon between the reservoir brine and CO2 under practical reservoir conditions. The laboratory experiments were conducted for the measurement of the IFT between CO2 and pure water or brine covering three interesting salinities (0 mg/L, 14224.2 mg/L and 21460.6 mg/L). Comparing the data of the CO2–pure water interfacial tension with other papers at 45 °C, at low pressures (<7.38 MPa), all data accord well; however, at high pressures (>7.38 MPa), all data have slight deviations. The dynamic and equilibrium IFT are measured as a function of pressure at the stratum temperature (97.53 °C). It is found that the dynamic IFT gradually approaches to a constant value, which is the equilibrium IFT. The equilibrium IFT decreases as the pressure increases but increases as the salinity increases. In addition, the wettability of the reservoir brine and CO2 system changes from the hydrophilic case to the hydrophobic case as the pressure increases, and the same phenomenon decreases as the salinity of brine increases.

Measurement of Interfacial Tension of CO2 and NaCl Aqueous Solution over Wide Temperature, Pressure, and Salinity Ranges

“…After the droplet became stable, the whole system was maintained for about 300 s so that it could reach equilibrium as shown in Figure . This step was used in the determination of the static value of the equilibrium IFT. ,,, An image of the droplet was then captured by the CCD camera and saved in the data acquisition system. Commercial software (DropMeter, MAIST) was used for image analysis and IFT calculation based on eq .…”

“…This step was used in the determination of the static value of the equilibrium IFT. 13,15,25,26 An image of the droplet was then captured by the CCD camera and saved in the data acquisition system. Commercial software (DropMeter, MAIST) was used for image analysis and IFT calculation based on eq 5.…”

“…Besides the aforementioned discrepancies in trends between pressure, temperature, and salinity, there are also discrepancies in the data themselves. The discrepancy in IFT in particular can reach 10 mN·m –1 , despite uniform conditions. , The research discussed here all used the pendant-drop method based on axisymmetric drop shape analysis (ADSA). Thus, aside from errors in applying this method, inconsistent condition settings, inadequate experimental protocols, or subsequent analytical techniques could be causes of these disparities.…”

Solid/CO 2 and solid/water interfacial tensions as a function of pressure, temperature, salinity and mineral type: Implications for CO 2 -wettability and CO 2 geo-storage

“…In this context, CO 2 /water interfacial tensions (γ cw ) can be determined experimentally (many studies reported this data e.g. Arif et al, 2016a;Li et al, 2012;Lun et al, 2012), however, an independent experimental measurement of solid/fluid interfacial tension is not possible because a solid interface is very different from a fluid-fluid interface due to absence of mobility (Li and Neumann, 1992). Consequently, the use of numerical/empirical techniques such as Neumann's equation of state becomes essential (Neumann et al, 1974).…”

RSM for Modelling the CO2 Effect in the Interfacial Tension Between Brine and Waxy Dulang Crude Oil During LSW-WAG EOR

“…IFT 700 was used for this section of the experiment. This equipment can measure the interfacial tension between liquid-liquid and gas-liquid and high pressure and high-temperature condition using either the pendant drop or rising drop method [27]. In the case of this experiment, the IFT was measured at reservoir temperature conditions 96°C and high pressure (ranging from 200 psi to 2000 psi).…”