Residual Oil Reservoir Recovery With Seismic Vibrations

Abstract

Summary Evidence suggests that certain vibrations, generated either by natural seismic events or by artificial explosions, have altered the production behavior of oil wells at distances as much as 200 km from the epicenter. These changes have affected the produced water/oil ratio: the water production rate increased from a formation that was at approximately the interstitial water saturation, while the oil rate increased in watered-out reservoirs that were near the residual oil saturation. Theoretical and field investigations of the phenomena suggest that vibrations may influence substantially the water or oil relative permeability that appears to be partially reconstituted at saturations that ordinarily would prohibit the flow of a particular phase. The key role is played by ultrasound oscillations, generated by seismic waves within the stratum, and it has been confirmed by in-situ measurements during the vibrostimulation of reservoirs. This paper provides an interpretation of the process and describes wave requirements, wave generation, and propagation in oil-bearing porous media supported by laboratory experiments and field cases of vibrostimulation of oil production from water-flooded reservoirs.