Numerical Simulation of Oscillating Pore Pressure Experiments and Inversion for Permeability

Abstract

AbstractAccurate knowledge of permeability is crucial for successful management of groundwater, petroleum resources, and subsurface contaminant remediation. The oscillating pore pressure method is a popular laboratory technique for permeability measurements of porous rock samples. We develop a novel data processing approach that utilizes a broad, multifrequency range of data and inverts it for permeability. We reprocess published data and demonstrate that our methodology outperforms traditional data reduction techniques, as our inversion results show a better fit to pressure trends. To better understand the effect of frequency on phase and amplitude data and to verify our inversion approach, we numerically simulate oscillating pore pressure experiments for four rock samples. We document a strong deviation of experimentally obtained phase data starting at 0.3 Hz oscillation frequency. A possible explanation for this deviation is poroelastic coupling during pressure diffusion. Our method can be used for robust determination of permeability and rapid prediction of experimental results using numerical simulation, ultimately improving the analysis of experimental permeability measurements.