Developing a novel procedure in utilizing pendant drop method for determination of ultra-low interfacial tension and surface tension in near-miscibility conditions

One of the procedures to measure the surface and interfacial tension (ST and IFT) is pendant drop tensiometry which has distinguished drawbacks to determine the ultra-low interfacial tension. The main drawbacks of previous pendant drop procedures were incapacitation for the drop formation at ultra-low IFT values, inability to provide a suitable photo for small needles, and drop formation with non-uniform discharges. Refer to the lack of a comprehensive method for measuring all ranges of IFT and ST from ultra-low to high values felt by considering the porous media limitation in many unique studies, such as enhanced oil recovery (EOR), and carbon capture and storage (CCS), to cover the fluid-fluid and gas-fluid interactions, improving the pendant drop method is to be crucial. In this study, a new procedure was introduced to measure the ultra-low IFT in order of 10-3 mN m-1 using different needles with an outer diameter (OD) of 31G (0.46 mm) to 34G. The needles were used in this study had OD from 34G (0.16 mm) to 14G (2.11 mm) to provide a wide range of IFT and ST values from ultra-low to high values. At last, a comprehensive table was made based on more than 450 IFT and ST results to assist the researchers in selecting the best type of needle for performing the pendant drop test according to the range of IFT and ST values by considering varied applications.

Automated summary

A new method was introduced in this study to measure ultra-low interfacial tension, using needles with different outer diameters to provide a wide range of surface and interfacial tension values from ultra-low to high. Furthermore, a comprehensive table was created based on the results to assist researchers in selecting the best needle for their experiments.