Wettability Alteration of Gas Condensate Reservoir Rocks to Gas Wetness by Sol-Gel Process Using Fluoroalkylsilane

摘要

Natural gas is becoming a very important energy source in recent years. A sharp reduction has been observed in gas deliverability in many low permeability gas reservoirs due to bottom-hole pressure drops below the dew point pressure. It is an established fact that altering the wettability of reservoir rocks from liquid wetness to gas wetness could improve the gas deliverability. In this study, a new polymeric surfactant coating for altering the wettability of Sarkhun reservoir rocks was prepared by using a sol-gel process. Perfluorodecylsilane (PFDS) and triethoxysilane (TEOS) were used to obtain an inorganic-organic network via hydrolysis and polycondensation reactions. The effect of this method was examined by various characterization tests such as FTIR, SEM, and EDX, static contact angle and imbibition tests for wettability alteration. The experimental results revealed that, the prepared polymeric network including the terminal fluorine groups were effective and provided sufficient repelling characteristics towards oil and water. Static contact angles were raised from 30 to 130° for water, and from <5 to 60° for condensate after sol-gel treatment.