Poroelastic wave propagation modelling of gas hydrate-bearing sediment based on tomographic microstructure data

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Accurate assessment of distribution and quantification of gas hydrate is hampered by a lack in knowledge how it interacts with its sediment frame, and can only be realized by remote seismic sensing. We propose to optimize effective medium modeling of the seismic wave velocity anomalies induced by gas hydrates in sediments. Laboratory samples varying in microstructure will be provided by laboratory syntheses, together with their ultrasonic/seismic laboratory data for model calibration/validation. 3-D distribution of all constituents (hydrate, ice, void, sediment) down to sub-µm spatial resolution will be derived by X-ray and Bragg tomography to understand the complex interaction of the hydrate and the host sediment at down to the grain contact scale. These data will be used as a direct geometrical input to high-performance computer simulations of wave propagation through the various well characterized microstructures on basis of a finite-difference rotated staggered grid algorithm. This algorithm provides for a parameter sensitivity study of effective viscoelastic properties on first principles. The study will be used to validate the available empirical model hypotheses about how the microstructures induce anomalies in wave attenuation of gas hydrate-bearing sediments.