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Modeling Wave Propagation in Cracked Porous Media with Penny-Shaped Inclusions
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 81st EAGE Conference and Exhibition 2019, Jun 2019, Volume 2019, p.1 - 5
Abstract
Most subsurface rocks generally contain saturated pores and cracks, where local (squirt) fluid flow (LFF) between pores and cracks (compliant pores) induces wave dispersion and attenuation. Some squirt-flow models have been proposed to model this phenomenon, based on the conservation of the fluid mass. We describe the oscillating squirt flow through penny-shaped inclusions based on the Biot-Rayleigh theory under the assumption of isotropically distributed cracks, i.e., randomly oriented, and derive the governing wave propagation equations from Hamilton's principle. The numerical modeling examples show that our results are in agreement with Gassmann equations at the low frequency limit and describes velocity dispersion and attenuation. In addition, the dependence on crack characteristics (such as radius, crack density and aspect ratio) is discussed. We find that crack radius affect the relaxation frequency of the squirt-flow attenuation peak, while the crack density and aspect ratio also affect the levels of dispersion and attenuation.