Experimental investigation of the impact of soybean oil-derived surfactant as a surface-active agent during gas well deliquification

Abstract

The inability of the gas rate to overcome the gas critical (minimum) flow rate leads to liquid loading in a gas well. To avoid premature well shut-in, the injection of surfactants is one of the standard methods used in gas well deliquification, although many commercial surfactants pose environmental toxicity concerns. This project investigates the suitability of biosurfactants in generating foam that will reduce the surface tension of the liquid by adsorbing at the liquid-gas interface to create a more significant mass than the liquid droplets which can be easily extracted from the walls of the wellbore. An experimental setup simulating gas well conditions introduce a surfactant derived from soybean oil, subjecting it to tests for foam stability, unloading efficiency, and dynamic surface tension. The results from the modified ASTM D-892 test show that Soybean Oil Derived Surfactant (SODS) exhibits promising surface tension reduction properties and effectively alters the gas-liquid interface. With the increase in concentration from 200 ppm, 400 ppm, and 600 ppm, the expelled water increased from 17%, 28%, and 70% respectively. Similarly, Gao-Rosen adsorption isotherms confirmed SODS appropriate for the prediction of the adsorption from solution with the R² values of approximately 1.0. This study introduces a cost-effective and environmentally friendly surfactant that performs favorably for gas well deliquification.