The layer‐by‐layer (LbL) self‐assembly technique is used to coat the surface of flow channels in microfluidic chips with geomaterials. The surface modifications diminish the discrepancy between the surface chemistry of synthesized microfluidic devices and those of underground porous rocks. Hence, the use of visual models and, in particular, microfluidic devices is broadened to simulate the multiphase flows and fluid–solid interactions in actual rocks. Glass and quartz substrates are successfully coated with silicon dioxide (SiO2), bentonite, and montmorillonite. On‐chip functionalization of polydimethylsiloxane (PDMS) and glass micromodels with SiO2 is also accomplished. The functionalized coatings using confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), and contact angle measurements are characterized. The surface modification technique is shown to be material‐independent, which generates a hydrophilic surface. The surface‐coated chips, functionalized by clay particles, are utilized to illustrate the role of water salinity on oil displacement.
Gas assisted gravity
drainage (GAGD) is an oil recovery mechanism
that can be implemented after waterflood to enhance the recovery of
oil. The performance of postwaterflood GAGD is affected by a variety
of parameters that determine the balance between capillary, gravitational,
and viscous forces. In this research, the influence of the wettability,
heterogeneities, and production rate on the recovery of oil have been
studied at the pore level to recognize phenomena affecting mechanisms
of oil recovery visualizing interfaces in a newly designed micromodel
that contains a coarse pore network covered by fine capillaries. Experimental
results show that regions with high oil saturation (oil-bank) were
formed ahead of the gas front in both oil-wet and water-wet micromodels
when the production rate was low. Under oil-wet conditions, the size
of the oil-bank was greater, and the recovery of oil initiated prior
to a gas breakthrough. Under water-wet conditions, the flow of the
residual oil after a gas breakthrough was initially restricted by
the presence of the residual water in small pores and fine capillaries.
However, high oil recovery was finally obtained upon an effective
reduction of the water saturation extending the time of the process.
Under both wettability conditions, increasing the drainage rate contributed
to the instability of gas fronts and early gas breakthroughs without
a remarkable oil recovery. The experimental result implies that, although
the oil production characteristics under oil-wet and water-wet conditions
are different, both of the wettability states have potential for the
implementation of postwaterflood GAGD.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.