Abstract
Complex flow dynamics have been observed, at the pore-scale, during
multiphase through porous rocks. These dynamics are not captured in
large scale models exploring the migration and trapping of subsurface
fluids e.g., CO2 or hydrogen. Due to limitations in imaging
capabilities, these dynamics cannot be observed directly at the larger,
Darcy scale. Instead, by using pressure data from pore-scale (mm-scale)
and core-scale (cm-scale) experiments, we show that fluctuations in
pressure measured at the core-scale reflect specific fluid displacement
events taking place at the pore-scale. The spectral characteristics of
the pressure data depends on the flow dynamics, size of the rock sample,
and heterogeneity of pore space. While high resolution imaging of large
samples would be useful in assessing flow dynamics across many of the
scales of interest, such an approach is currently infeasible. We suggest
an alternative, pragmatic, approach examining pressure data in the
time-frequency domain using wavelet transformation.