Microfluidics is an appealing method
to study processes at rock
pore scale such as oil recovery because of the similar size range.
It also offers several advantages over the conventional core flooding
methodology, for example, easy cleaning and reuse of the same porous
network chips or the option to visually track the process. In this
study, the effects of injection rate, flood volume, micromodel structure,
initial brine saturation, aging, oil type, brine concentration, and
composition are systematically investigated. The recovery process
is evaluated based on a series of images taken during the experiment.
The remaining crude oil saturation reaches a steady state after injection
of a few pore volumes of the brine flood. The higher the injection
rate, the higher the emulsification and agitation, leading to unstable
displacement. Low salinity brine recovered more oil than the high
salinity brine. Aging, initial brine saturation, and the presence
of divalent ions in the flood led to a decrease in the oil recovery.
Most of the tests in this study showed viscous fingering. The analysis
of the experimental parameters allowed to develop a reliable and repeatable
procedure for microfluidic water flooding. With the method in place,
the enhanced oil recovery test developed based on different variables
showed an increase of up to 2% of the original oil in place at the
tertiary stage.
The goal of this article is to test the potential application of lignosulfonates (LSs) in crude oil production and processing. Three LS samples of varying hydrophobicity and average molecular weight were considered. First, the interfacial tension between brine and xylene and interfacial dilational rheology properties of LS samples were measured. It was found that the most surface-active LS sample has the lowest molecular weight in agreement with the results from the literature. In the presence of asphaltenes, all three LS samples were able to compete with asphaltenes, the most polar crude oil component, at the interface and form mixed LS−asphaltene interfaces. However, only the most surface-active LS sample among the three tested could fully desorb asphaltenes at the highest tested LS concentration (500 ppm). Second, three possible applications were screened. LSs were tested to prevent the formation of w/o crude oil emulsions or to break these. However, the opposite effect was observed, that is, stabilization of water-in-crude oil emulsions. The potential application of LS in produced water (PW) clarification was furthermore considered. The kinetics of PW clarification was found unaffected by the presence of LS, even at very high concentrations (1000 ppm). Finally, the potential of LS for enhanced oil recovery was assessed. The LS flood changed the surface wettability toward water wetness for one of the samples, yet LS injection did not recover additional oil beyond brine recovery. It was concluded that LS has interesting properties, such as the potential to compete with crude oil indigenous components at the oil/water interface. The stabilization action of LS was dominant over any destabilization effect, which led to the conclusion that LSs are more efficient for stabilizing emulsions rather than destabilizing.
Microfluidics methods offer possibilities for visual observations of oil recovery processes. Good control over test parameters also provides the opportunity to conduct tests that simulate representative reservoir conditions. This paper presents a setup and procedure development for microfluidic oil recovery tests at elevated temperature and pressure. Oil recovery factors and displacement patterns were determined in single- or two-step recovery tests using two crude oils, high salinity salt solutions and low salinity surfactant solutions. Neither the displacement pattern nor the recovery factor was significantly affected by the pressure range tested here. Increasing temperature affected the recovery factor significantly, but with opposite trends for the two tested crude oils. The difference was justified by changes in wettability alteration, due to variations in the amounts and structure of the acidic and basic oil fractions. Low salinity surfactant solutions enhanced the oil recovery for both oils.
Surface wettability has a crucial impact on drop splashing, emulsion dynamics, slip flow for drag reduction, fluid-fluid displacement, and various microfluidic applications. Targeting enhanced oil recovery (EOR) applications, we experimentally...
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.