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Prof. Boris Gurevich of Curtin U. (Australia) and CSIRO presents “Seismic attenuation and dispersion in fluid-saturated rocks – estimates and bounds” at the MIT Earth Resources Laboratory.
This talk will be streamed live on our Youtube Channel.
“Estimating the impact of solid pore fill on effective elastic properties of rocks is important for a number of applications such as seismic monitoring of production of heavy oil or gas hydrates. We develop a simple model relating effective seismic properties of a rock saturated with a liquid, solid, or viscoelastic pore fill, which is assumed to be much softer than the constituent minerals. A key feature of the model is division of porosity into stiff matrix pores and compliant crack-like pores because the presence of a solid material in thin voids stiffens the rock to a much greater extent than its presence in stiff pores. We approximate a typical compliant pore as a plane circular interlayer surrounded by empty pores. The effect of saturation of the stiff pores is then taken into account using generalized Gassmann’s equations. The proposed model provides a good fit to measurements of the shear stiffness and loss factor of the Uvalde heavy-oil rock at different temperatures and frequencies. When the pore fill is solid, the predictions of the scheme are close to the predictions of the solid squirt model recently proposed by Saxena and Mavko. At the same time, the present scheme also gives a continuous transition to the classic Gassmann’s equations for a liquid pore fill at low frequencies and the squirt theory at high frequencies. In addition, we derive rigorous bounds for attenuation and dispersion in fluid-saturate rocks, and use the proposed model to prove that these bounds are realisable.”
Boris Gurevich has MSc from Moscow State University (1981) and PhD from Moscow Institute of Geosystems (1988). In 1990s he worked at a number of institutions in Russia, Germany, UK and Israel before joining Curtin University and CSIRO in Perth, Australia in 2001 as Professor of Petroleum Geophysics. In 2010-2015 he served as head of Curtin’s Department of Exploration Geophysics. He is currently Director of the Curtin Reservoir Geophysics Consortium. In 2014 he spend a sabbatical semester at the ERL and keen to return at some point. His research interests include rock physics, poroelasticity, diffraction imaging, time lapse seismic monitoring and CO2 sequestration.