Wettability alteration of reservoir rocks to gas wetting condition: A comparative study

Abstract

AbstractProductivity of gas condensate reservoirs reduces significantly due to the near wellbore condensate/water blockage phenomenon. A novel, permanent solution to alleviate this problem is near wellbore wettability alteration of reservoir rocks to preferentially gas wetting conditions; industrial chemical materials are good candidates for this purpose, because of their eco‐friendly characteristics, economical price, and mass production. In this paper, a comparative study is conducted on two industrial fluorinated chemicals, MariSeal 800 and SurfaPore M. Static and dynamic contact angle measurements, spontaneous imbibition, and core flooding tests were conducted to investigate the effect of utilized chemical agents on surface wetting behaviour and fluid flow characteristics of rock samples. Contact angle measurements demonstrate that the liquid phase is changed to a non‐wetting phase after chemical treatment and MariSeal 800 has a greater potential to decrease the surface free energy of the calcite surface. Although both chemicals reveal great potential in static contact angle measurements, further experiments were conducted to distinguish between their abilities. Spontaneous air liquid imbibition tests and endpoint relative permeability measurements approved the potential of utilized chemicals to improve liquid phase mobility and decrease critical condensate saturation, which improve production parameters and reservoir productivity. Liquid phase endpoint relative permeabilities of sandstone core samples were improved by factors of 1.74 and 2.62; furthermore, irreducible liquid phase saturations were decreased by factors of 0.68 and 0.5 using MariSeal 800 and SurfaPore M chemicals. The results of this research help efficient selection of chemical agents for further field applications.