Microfluidics Technology for Visualizing Surfactant Performance in Enhanced Oil Recovery
J. Kim, E. Willmott and L. Quintero
Event name: IOR 2019 – 20th European Symposium on Improved Oil Recovery
Session: Coffee Break / Poster Session Day 1
Publication date: 08 April 2019
Info: Extended abstract, PDF ( 6.44Mb )
Price: € 20
This paper introduces a microfluidic technology for surfactant evaluation for Enhanced Oil Recovery (EOR). During EOR surfactant development process, each developed surfactant formulation for a targeted reservoir must undergo oil recovery performance testing using conventional methods such as sandpack and coreflood test. Although these are beneficial testing tools, testing protocols and labor requirements can be quite time-consuming and expensive. The microfluidic system developed in this study accelerates surfactant selection process in a rapid, more convenient, and cost effective manner. It can be utilized as a fast screening tool to select candidate surfactant formulations for the final validation with core flood testing. It also offers superior visualization of oil-surfactant interactions to provide better understanding of what is occurring inside a reservoir that was not previously possible with conventional testing methods. The newly developed microfluidic system utilizes porous media that resembles reservoir sandstone in terms of reservoir pore structure, wettability, and polarity. Initially, the porous media is filled with crude oil to be aged in-situ overnight at reservoir temperature and moderate pressure. Injection water is then injected into the porous media to simulate secondary recovery water flooding. For the residual oil left behind, a surfactant flood is injected, followed by additional water injection. The progression of oil recovery throughout the whole process is video recorded for visual assessment of surfactant performance. The collected images are analyzed to quantify the amount of oil recovery. The experimental results confirmed that the microfluidic system can differentiate oil recovery performance among good, average, and poor performing surfactants. A systematic study showed that the microfluidic technique gives higher data resolution to differentiate surfactant performance than sandpack method and reasonable repeatability when wettability is controlled. Furthermore, the details of oil recovery process inside porous media through the interaction between oil and surfactant and the formation of microemulsion is vividly exhibited in a transparent microfluidic reservoir. Depending on the surfactant type and efficacy, the effectiveness on oil recovery varies. This variation in surfactant performance was noticeable by comparing the digital images of residual oil in microfluidic porous media after flooding with different surfactants, enabling another level of chemical evaluation, which was not possible with conventional testing methods. The quantified oil recovery data was similar to those of conventional sandpack and core flood tests, but obtained faster by a few days up to a few weeks with less operational difficulty.