Rheological Assessment of Oil-Xanthan Emulsions in Terms of Complex, Storage, and Loss Moduli

This experimental assessment was carried out to study the viscoelastic performance of crude oil-xanthan emulsions employing a RheoStress RS100 rheometer. Crude oil with a concentration range of 0-75% by volume was used to prepare the oil-gum emulsions. Two xanthan gums of Sigma and Kelzan were added in the emulsions with concentration ranges of 0-10(4) ppm. The linear viscoelastic ranges of all the tested oil-gum emulsions were found in the range of 0.1-10 Pa. Thus, the experimental tests were completed within the linear viscoelastic range of 1 Pa. The complex modulus increased gradually and steadily with frequency and gum concentration for all the examined emulsions. The addition of crude oil into the lighter xanthan concentration of <10(3) ppm provided almost the same behavior as the xanthan solution, whereas the presence of crude oil within the higher xanthan concentrations significantly stimulated the measured values of the complex modulus. For lower gum concentrations of up to 1000 ppm, oil concentration displayed no effect on both the storage and loss moduli, whereas for gum concentrations higher than 1000 ppm, both moduli increased gradually with crude oil concentration.

Automated summary

This study conducted experimental assessments using a RheoStress RS100 rheometer to investigate the viscoelastic properties of crude oil-xanthan emulsions. Emulsions were prepared by mixing crude oil with concentrations ranging from 0 to 75% volume with two xanthan gums (Sigma and Kelzan) at concentrations ranging from 0 to 10(4) ppm. The linear viscoelastic range of all tested emulsions was found to be between 0.1-10 Pa. The complex modulus increased steadily with frequency and gum concentration, and the presence of crude oil significantly affected the measured values of the complex modulus at higher xanthan concentrations.