Squirt flow in partially saturated cracks: a simple analytical model
نویسندگان
چکیده
SUMMARY Obtaining the seismic response of rocks containing cracks whose scales are much smaller than prevailing wavelengths is a classic and important problem in rock physics. Seminal analytical models yield signatures cracked saturated with single fluid phase. However, wide variety practically relevant scenarios, may be partially multiple immiscible fluids contrasting compressibilities, such as gas water. When passing wave deforms medium, pressure gradients arise within cracks, which, turn, tend to relax through process commonly known squirt flow. The corresponding viscous dissipation greatly affect amplitudes velocities, well anisotropic behaviour medium. To date, extensions classical include flow occurring isolated remain limited either saturation or frequency range. In this work, we present simple model compute aligned accounting for effects. First, solve linearized Navier–Stokes equations penny-shaped crack subjected an oscillatory strain. Then, obtain closed expression complex-valued frequency-dependent effective bulk modulus which accounts stiffness variations each due Using medium models, together saturating fluid, retrieve compliance matrix probed rock. proposed solution validated by comparison 3-D numerical simulations existing models.
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ژورنال
عنوان ژورنال: Geophysical Journal International
سال: 2021
ISSN: ['1365-246X', '0956-540X']
DOI: https://doi.org/10.1093/gji/ggab249