Low-Frequency Dynamic-Stress Effects On Core-Scale Porous Fluid Flow Due To Coupling With Sub-Pore-Scale Particle Interactions

It has been observed repeatedly that low-frequency (1-500 Hz) seismic stress waves can enhance oil production from depleted reservoirs and contaminant extraction from groundwater aquifers. The physics coupling stress waves to fluid flow behavior in porous media is still poorly understood. Numerous underlying physical mechanisms have been proposed to explain the observations. Core-scale experiments were performed to investigate one of these proposed mechanisms, the coupling of dynamic stress to sub-pore size particle (colloid) interactions with solid surfaces. This is an important mechanism because it can produce profound changes in porous matrix permeability due to either accumulation or release of natural colloids. Core-scale porous flow experiments demonstrated that both natural (in-situ) and artificial (injected) colloids can be released from the pores by applying dynamic stress to sandstone cores at frequencies below 100 Hz. Results are shown for release of in-situ particles from Fontainebleau sandstone induced by applying dynamic stress at 26 Hz.