Numerical Analysis of Simulation Accuracy for Seepage Change in One-Dimensional Layer Under Low-Frequency Wave

Abstract

The parameter analysis of petrophysical properties could be beneficial for explaining the action mechanisms of wave stimulation technique, which coupled the original Darcy flow field with the low-frequency wave field. Spurious reflection occurring at the artificial boundaries in general Biot consolidation problem caused by the wave field would affect the simulation accuracy. The consistence requirement for directions of wave propagation, flow velocity, and soil spreading in one-dimensional model had increased the difficulty for obtaining reasonable results. Strategies as addition of PMLs, model size optimization, approximation order adjustment of shape functions, and proper mesh generation were investigated in sequence with the system COMSOL to improve the accuracy of results. Several schemes were compared in each strategy. Periodic variation over time and sharp decline over distance of petrophysical properties and were observed, which agree with general experimental cognition of the wave stimulation technique. The grid shape would influence simulation accuracy and a better distribution of pore pressure was found with quadrilateral mesh generation in the one-dimensional physical model. Consistence in x-coordinate of nodes contributed to a parallel fluctuation of properties. A comparison between the numerical results and approximate analytical solutions was made at the end, which had verified the advantage of numerical solution on mechanism explanation. Further analysis for choosing proper operating parameters of wave stimulation technique might be helped.