Experimental study of the surfactants effects on gas phase mass transfer coefficients in gas condensate reservoirs

Abstract

Surfactant flooding in gas-condensate reservoirs, shown to be an effective treatment method to remediate condensate blockage in near well bore regions, have been the focus of several studies in the recent decades. However, the effect of these chemicals on the gas phase mass transfer coefficients has not been yet addressed though they have to be incorporated in non-equilibrium compositional simulators to imitate the reservoir behavior reliably. Besides, any knowledge of the overall effect of the surfactants on these coefficients can shed light on the side effects of the surfactant flooding on mass transfer phenomenon and evaluate its suitability as a treatment strategy.In this study, separate empirical correlations were developed for methane and isobutane representing light and intermediate components respectively in the absence and the presence of surfactants at the temperature of 40 °C. In all the developed correlations for both components in the presence of surfactants, while spreading coefficient has a positive exponent, equilibrium adsorption constant possesses a negative exponent. This implies that surfactants with a larger former parameter and a smaller latter parameter like SDS have more opportunity to enhance the volumetric mass transfer coefficient. The results also confirm the positive effect of pore gas velocity on gas phase mass transfer coefficients even in low gas flow rates. Similarly, this effect has already been reported in NAPL (Non Aqueous Phase Liquid) volatilization related studies. Effective diffusion coefficient, condensate saturation, mean grain size, component type, surfactant type and residual water saturation were also shown to affect these mass transfer coefficients. In addition, it has been shown that surfactants which are conventionally believed to reduce volumetric mass transfer coefficients in gas-liquid systems like bubble columns, improve gas phase mass transfer coefficients in gas condensate reservoirs. This improvement is considered a drawback for the cited technique.