Stimulated Oil Production by Seismic Waves

We imagine an oil reservoir being produced through the use of injection and extraction wells. The oil production in the field, through time, has fallen to low levels; water may be flowing, but much of the oil has become effectively stuck, left behind by the front of the oil that is still connected to the production well. The remaining oil patches may be present at economically significant volume fractions; e.g., 30\% of the pore space might commonly be occupied by stuck oil. Our main quest ions are: How does a seismic wave influence the formation of droplets, and how may it be used to re-mobilize this oil? What are the quantitative relationships between the seismic oscillations and the changes of the capillary interfaces that are associate d with the oil production and net flow? In particular, what are the flow laws that describe this? What are the pore-scale mechanisms that govern these processes, and how may they be understood and quantified? To answer these questions simulations and expe riments where these changes are captured are needed. The theoretical, experimental and computational approaches to address these questions are organized as follows: The theory provides the link between the simulations and model experiments on the one ha nd with the field observations on the other. The theoretical developments justify a major simplification in the simulations and experiments, i.e. the replacement of the seismic wave by a periodic force in the fluid. The simulation model we will apply is the now well established lattice Boltzmann model for imiscible fluids, and the experiments based on a established techniques using transparent, quasi-twodimensional cells . With the lattice Boltzmann model the full motion of the oil-water interfaces w ithin the porous medium may be computed. Likewise, in the experiments the interface motion may be visualized and recorded. Very detailed comparison between simulations and theory is therefore possible.