Two phase polymer flooding experiments were carried out using a novel Lab-on-a-Chip experimental set up. The microfluidics device uses porous Glass-Silicon-Glass (GSG) micro-models which were constructed based on reservoir rock thin section. The model attempts to resemble the thin sections internal porous structure geometry but also the rock wettability. The results were monitored and analyzed in real time using an image analysis algorithm.
Polymer flooding is widely used to obtain incremental oil recoveries through providing favorable mobility ratio. However, its ability to mobilize and displace oil at microscale through its viscoelastic properties is still debated. EOR flooding experiments performed in micromodels that resemble porous media provides continuous visual access that combined with quantitative image analysis can provide improved understanding on displacement mechanisms. In particular, the more difficult questions concerning the complex viscoelastic behavior of polymers and its role in mobilizing trapped oil. In addition, when verified, micromodel based flooding can provide a complement to experimentation on limited core samples.
The experimental results did not show a significant increase in oil recovery due to viscoelasticity in the micromodels used at the preset experimental conditions. GSG micromodels were successfully implemented under reservoir temperature for flooding experiments. Additionally it was found that using an extended Cox-Merz Plot (relation between Rheological parameters) to describe the rheology will improve the interpretation of the phenomena taking place; as well as considering the elongational rheology of aqueous polymer solutions.
The results presented in this work show that flooding experiments in micromodels have a great potential to improve chemical EOR screening processes. The visualization technology depeloped during this work will contribute significantly and can be the enabler of intensified application of microfluidics technologies in EOR.