In this paper, we present a new generation of micromodels that will significantly improve the investigation of "Enhanced Oil Recovery (EOR)" processes under in-situ reservoir conditions (p, T). The micromodels presented will be used as an integral part of the surfactant selection process and are considered a useful tool among phase behavior testing and core floods.
The micromodel developed is a sandwich of different materials; Glass-Silicon-Glass (GSG). The porous structure is completely dry etched through the silicon which results in a transparent micromodel. The GSG - micromodels presented in this study show several advantages over "conventional" micromodels made of silicon, PDMS or glass: (1) they are transparent, hence, enable more flexible image gathering, (2) permit the construction of small pore-throats and complex flow geometries and (3) facilitate the investigation of transport processes at high p, T.
The wettability of the micromodel is controlled using nanotechnology based coatings which are critical to run micromodel flooding experiments under predefined conditions. The nanocoating technology can be best described by densely packed molecular piles bound to the surface via strong covalent bonds. Therefore, excellent hydrolytic, chemical and thermal stability of the nanocoatings is observed.
The paper discusses micromodel construction, surface modification and experimental setup and will show how the microfluidic technology can be used to rapidly screen suitable surfactant solutions for "Enhanced Oil Recovery (EOR)" applications.
Results show that microfluidic technology give detailed pore-level insights into multi-phase displacement of oil by surfactant solutions including percolation of emulsions. Further, if applied they can accelerate the surfactant screening process and considerably reduce the amount of required core floods. Hence, microfluidic surfactant screening be considered an integral part of the surfactant solution selection process in the future.