TY - GEN

T1 - Screening of EOR Potential on the Pore Scale - Application of Microfluidics to Alkaline Flooding

AU - Ott, Holger

AU - Kharrat, Ahmad

AU - Borji, Mostafa

AU - Clemens, Torsten

AU - Arnold, Pit

PY - 2019/4

Y1 - 2019/4

N2 - Complex chemical EOR processes, such as in alkaline or surfactant flooding, aretypically optimized on their phase behavior and by core flood experiments. However,the information from classical experiments are rather limited, because they do notdirectly give insight the details of oil mobilization and displacements – in core floods,typically oil production and differential pressure are measured, which are both 1Ddata sets. The phase behavior is typically measured in test tubes and not underrealistic flow (mixing) conditions in porous media flow. Chemical EOR is changinginteractions between fluids and the porous medium and is therefore manifested onthe pore scale, where fluids are actually displaced. However, pore scale observationsare typically suffering from a limited field of view especially for multiphase floweffects, which may not be representative for the overall system or the displacement.In the frame of this study, we investigate displacements of crude oil by water andalkali solutions in order to optimize injection-water compositions for tertiary recovery.The study takes advantage of the high spatial and temporal resolution of microfluidicsin order to observe fluid phases in the pore space, their distribution anddisplacements. Changes of the wetting state, breaking of oil clusters and theformation of emulsion phases as characteristic for the displacements have beenobserved. In order to overcome the limitation of the relatively small field of view, oilclusters have been analyzed by statistical and topological means showing asystematic change form water flooding to EOR.The study shows that (a) cluster analysis can be used for EOR screening and – in thepresent case – is more indicative with respect to EOR performance than productiondata from the same experiment. The study might be a first step towards statisticalfingerprinting for optimizing EOR processes. (b) classical phase behaviorexperiments do not reflect (or just partly) the phase behavior in the porous mediumunder flow conditions. (c) the formation of (micro) emulsions in the pore space leadsto pinning effects and is therefore of disadvantage for the displacement.

AB - Complex chemical EOR processes, such as in alkaline or surfactant flooding, aretypically optimized on their phase behavior and by core flood experiments. However,the information from classical experiments are rather limited, because they do notdirectly give insight the details of oil mobilization and displacements – in core floods,typically oil production and differential pressure are measured, which are both 1Ddata sets. The phase behavior is typically measured in test tubes and not underrealistic flow (mixing) conditions in porous media flow. Chemical EOR is changinginteractions between fluids and the porous medium and is therefore manifested onthe pore scale, where fluids are actually displaced. However, pore scale observationsare typically suffering from a limited field of view especially for multiphase floweffects, which may not be representative for the overall system or the displacement.In the frame of this study, we investigate displacements of crude oil by water andalkali solutions in order to optimize injection-water compositions for tertiary recovery.The study takes advantage of the high spatial and temporal resolution of microfluidicsin order to observe fluid phases in the pore space, their distribution anddisplacements. Changes of the wetting state, breaking of oil clusters and theformation of emulsion phases as characteristic for the displacements have beenobserved. In order to overcome the limitation of the relatively small field of view, oilclusters have been analyzed by statistical and topological means showing asystematic change form water flooding to EOR.The study shows that (a) cluster analysis can be used for EOR screening and – in thepresent case – is more indicative with respect to EOR performance than productiondata from the same experiment. The study might be a first step towards statisticalfingerprinting for optimizing EOR processes. (b) classical phase behaviorexperiments do not reflect (or just partly) the phase behavior in the porous mediumunder flow conditions. (c) the formation of (micro) emulsions in the pore space leadsto pinning effects and is therefore of disadvantage for the displacement.

KW - Fluid Dynamics

KW - Multiphase Flows

M3 - Conference contribution

BT - DGMK/ÖGEW-Frühjahrstagung 2019

ER -