Rapid Determination of Interfacial Tensions in Nanopores: Experimental Nanofluidics and Theoretical Models

Abstract

A rapid and accurate determination of interfacial tensions (IFTs) in nanopores is scientifically and practically significant, while most existing experimental measurements are restricted to the micrometer scale and theoretical calculations are relatively limited. In this study, six series of the IFT measurement tests for the binary CO2–C10, C1–C10, and N2–C10 mixtures are conducted at temperatures (T) of 25.0 and 53.0 °C in a self-manufactured nanofluidic system. Moreover, a nanoscale-extended equation-of-state model considering the effects of the confinement, intermolecular interactions, and disjoining pressure and a semianalytical correlation are proposed to calculate the IFTs of the three mixtures in bulk phase and nanopores. Third, a new Tolman length formulation is developed for the IFT corrections in nanopores. Overall, the calculated IFTs from the two theoretical methods agree well with the measured results for most cases in nanopores. On the other hand, effects of the pore scale, temperature, pressure, and fluid composition on the IFTs of the three mixtures are effectively validated and specifically investigated. One suggestion comes from this work that the two theoretical methods for calculating the IFTs are better to be applied concurrently to minimize errors. Another important future work is to include more pore surface parameter (e.g., wettability) into the theoretical model.

Stability Analysis and Two-Phase Flash Calculation for Confined Fluids in Nanopores Using a Novel Phase Equilibrium Calculation Framework

“…We test the phase behavior of CO 2 - n -decane ( n -C 10 ) − and CH 4 - n -C 10 − systems. The results for testing IFT in nanopores are presented in section 2 of the Supporting Information.…”

Minireview of Microscopic CO2 Interactions with Fluids and Minerals in Shale: Advances and Outlook

“…The IFT between CO 2 and oil at the nanoscale is not always smaller than the bulk value and is affected by pressure and temperature conditions. Zhang et al 66 calculate IFT between CO 2 and decane (Figure 10b) and found that the IFT in nanometer pores is lower than that in the bulk at low pressures. However, when the pressure increases to 9.6 MPa, the IFT in nanometer pores becomes larger than that in the bulk.…”

A Determination Method of CO2-Oil Miscible State in the Heterogeneous Low-Permeability Reservoir

“…In the oil industry, most of the CO 2 -EOR projects were implemented in miscible phase (CO 2 miscible flooding) [5][6][7]. During the process of CO2 flooding, the miscibility state of CO2-oil can be judged by the minimum miscibility pressure (MMP), which not only affects the displacement efficiency, but also affects the CO 2 storage efficiency [8].…”