Surfactant induced reservoir wettability alteration: Recent theoretical and experimental advances in enhanced oil recovery

Abstract

Reservoir wettability plays an important role in various oil recovery processes. The origin and evolution of reservoir wettability were critically reviewed to better understand the complexity of wettability due to interactions in crude oil-brine-rock system, with introduction of different wetting states and their infl uence on fl uid distribution in pore spaces. The effect of wettability on oil recovery of waterflooding was then summarized from past and recent research to emphasize the importance of wettability in oil displacement by brine. The mechanism of wettability alteration by different surfactants in both carbonate and sandstone reservoirs was analyzed, concerning their distinct surface chemistry, and different interaction patterns of surfactants with components on rock surface. Other concerns such as the combined effect of wettability alteration and interfacial tension (IFT) reduction on the imbibition process was also taken into account. Generally, surfactant induced wettability alteration for enhanced oil recovery is still in the stage of laboratory investigation. The successful application of this technique relies on a comprehensive survey of target reservoir conditions, and could be expected especially in low permeability fractured reservoirs and forced imbibition process.

Wettability modification and its influence on methane adsorption/desorption: A case study in the Ordos Basin, China

“…After draining and depressurizing, the flow capacity of the formation fluid can gain a positive alteration due to the factors such as the wettability modification, increase of the relative permeability of gas/water, and reduction of the capillary pressure (or even transform into a driving force), leading to the reduction of liquid-lock phenomenon, and eventually allowing the fluid to flow to the wellbore, thus improving gas production. 26,[75][76][77] From the microscopic point of view, the methane adsorption capacity of sample is significantly increased after applied the G502 in this research. It is experimentally proven that gas (methane) wettability of coal is lower than that of the moisture.…”

Mechanism governing nanoparticle flow behaviour in porous media: insight for enhanced oil recovery applications

“…As all carbonate reservoirs are suggested to be oil-wet [43]. Therefore, the right nanoparticle and optimum concentration of the nanoparticle is required.…”

Study of Spontaneous Imbibition of Water by Oil-Wet Sandstone Cores Using Different Surfactants

“…In recent years, many researchers have studied the relationship between core imbibition recovery and reservoir wettability. [13][14][15][16][17][18][19][20] Zhou et al [17] investigated the interrelationship of wettability and oil recovery by spontaneous imbibition and concluded that the stronger the core surface hydrophilicity, the higher the imbibition recovery. In the present paper, different types of surfactants were used to vary the wettability of the core surface, while maintaining a constant oil-water IFT, to study the relationship between reservoir wettability and ultimate imbibition recovery.…”