Dynamic Molecular Modeling and Experimental Approach of Fluorocarbon Surfactant-Functionalized SiO₂ Nanoparticles for Gas-Wettability Alteration on Sandstones

Abstract

Fluorocarbon surfactants have been widely used to promote gas-wetting alteration of sandstones with the objective of inhibiting the formation damage due to condensate banking and hence increasing the oil recovery. This study is focused on understanding the behavior of the wettability alteration from a liquid-wet state to gas-wettability by SiO 2 nanoparticles functionalized with 20 wt % of a commercial fluorocarbon surfactant Silnyl FSJ (SY) using molecular dynamics simulations and experimental approaches. The SY-functionalized SiO 2 nanoparticles were synthesized by an incipient wetness method. Then, three nanofluids were obtained by dispersing the modified SiO 2 nanoparticles at 0.3, 0.5, and 0.7 wt % in a KCl brine (2 wt %) and were employed for wettability alteration of the oil-wet sandstone samples under room conditions. Changes of the samples' wettability were estimated by experimental contact angle measurements in brine/ rock/air and n-decane/rock/air systems. The theoretical evaluation was made using molecular dynamics for reproducing the coating of the sandstone samples with the SY-functionalized nanoparticles and the contact angles measured experimentally. Further, the wettability alteration to a gas-wet system is described from a physical insight based on the thermodynamic analysis of the interaction energies of nanoparticles−liquid, surfactant−liquid, and liquid−liquid. The molecular model developed in this study allows predictive calculations of the contact angle of liquid droplets, with deviations lower than 7% regarding the experimental value. The theoretical approach allows optimizing the use of surfactant-functionalized nanoparticles for promoting the wettability alteration from liquid-wet to gas-wet state, which can lead to cost savings and increase the performance of improved and enhanced oil recovery processes.

The effect of nanoparticles on reservoir wettability alteration: a critical review

“…Moreover, Moncayo-Riascos et al (2019) studied the behaviour of wettability alteration from liquid wet to gas wet by SiO 2 nanoparticles functionalized with fluorocarbon surfactant Silnyl FSJ (SY). They proved that the SYfunctionalized SiO 2 nanofluid can alter the wettability of the sandstone rock from oil wet to gas wet (Moncayo-Riascos et al 2019).…”

An Enhanced Carbon Capture and Storage Process (e-CCS) Applied to Shallow Reservoirs Using Nanofluids Based on Nitrogen-Rich Carbon Nanospheres

“…[29]. Nanoparticles have been used to increase the recovery of oil and gas by modifying the physicochemical properties of the reservoirs [30,31], and to modify reservoirs’ wettability, asphaltenes adsorption, catalysis and stabilization of fines in reservoirs, among others [30,32,33,34,35]. The obtained results demonstrate their effectiveness in achieving this objective without obstruction of the porous media.…”

Theoretical and Experimental Approach for Understanding the Interactions Among SiO2Nanoparticles, CaCO3, and Xanthan Gum Components of Water-Based Mud

“…The mineral surfaces are constructed with a width of 30 Å and a surface area of 300 × 300 Å 2 , using a total of 13 824 and 12 960 atoms for constructing the sandstone and calcite, respectively. The surface dimension was selected to ensure that the molecules of the liquid phase do not have interactions between their periodic images. ,, A distance of 300 Å is deemed sufficient, whereas a width of 30 Å was used since it is 2 times larger than the typical cutoff radius (12 Å) defined for modeling polymer systems. , This configuration has been widely implemented to describe solid–liquid systems by molecular dynamics simulation. ,,, The NP was constructed using 3120 SiO 2 molecules with a particle diameter of 4.5 nm, using a silanol surface density of 8 OH/nm 2 , to ensure the proper description of the hydrophilic state of the SiO 2 NP and proper description of the water–NP interaction energy. ,, …”

“…Molecular dynamics simulations have been recently employed to provide a theoretical understanding of several phenomena in the petroleum industry, including wettability alteration, − aggregation behavior of asphaltenes, − and interfacial behavior. − These phenomena were substantially improved through NP application, while molecular dynamics simulation provided an insight into the mechanisms of improvement. − Despite the potential advantages of applying theoretical studies to drilling fluids, such studies are less common in the literature. Molecular dynamics simulation has been conducted to determine the mechanism of clay hydration and swelling, , methane dissolution and diffusion through drilling fluids, and the interaction between clay minerals and swelling inhibitors to improve the design of drilling fluid additives .…”