Seismic characterization of poroelastic structures using the theory of stochastic wave propagation and finite-difference simulations
Final Report Abstract
Central result is the theoretical analysis of the conversion scattering mechanism from propagating wave modes into diffusion waves in randomly inhomogeneous poroelastic solids and the formulation of a dynamic-equivalent medium theory in 3D space in analogy to the generalized O'Doherty-Anstey theory for scattering in elastic solids. It has become apparent that the diffusion wave conversion scattering mechanism (fast P --> slow P-wave) is a major source of seismic wave dissipation in the frequency band relevant for seismic exploration. On the basis of these results several rock physics models have been developed including models for the acoustic signatures of a) partially saturated rocks, b) strong permeability fluctuations. These models enabled the quantitative interpretation of laboratory experiments on core samples carried out by our collaborators at Curtin University of Technology. Another major achievement is the simulation of this wave conversion scattering mechanism using a modified finite-difference scheme in 2D and conventional finite-element scheme in 3D. For the first time we were able to demonstrate and quantify the attenuation anisotropy due to the wave-induced flow mechanism. These numerical results triggered the development of further theoretical analysis leading to the so-called generalized poroelastic Backus theory. Though not originally planned, the quasi-static finite-element simulations provided a useful means to analyze the spatio-temporal evolution of fluid-induced micro-earthquakes in stressed rock masses. In collaboration with the tectonic stress group a new understanding of the coupling between fluid pressure and regional stress field has been elaborated. Indicators of the success and impact of the research carried out by the junior research group include a) more than 25 peer-reviewed publications in international journals of geophysical and applied physics scope, b) award from the Australian Society of Exploration Geophysicists, c) participation in a couple of still on-going, industry-funded projects, d) creation of a seismic rock physics research team at the division of Earth Science & Resource. Engineering of CSIRO (established in September 2008 and lead by T. Müller since then) that continues the research along the lines of the junior research group. In conclusion, the continuing funding of Phase I and II within the Emmy-Noether program enabled the development of a sound theoretical basis of fluid-rock interactions constituting a fundamental contribution to the vastly growing field of rock physics. The research outcome continues to trigger industry-funded projects in the realm of oil and gas reservoir characterization, geo-sequestration of carbon dioxide, and unconventional resources exploration.
Publications
- Wave-induced fluid flow in random porous media: Attenuation and dispersion of elastic waves. Journal of the Acoustical Society of America, Vol. 117. 2005, Issue 5, pp. 2732-2741.
Müller, T. M., Gurevich, B.
(See online at https://dx.doi.org/10.1121/1.1894792) - Comparative review of theoretical models for elastic wave attenuation and dispersion in partially saturated rocks.
Soil Dynamics and Earthquake Engineering, Vol. 26. 2006, Issues 6–7, pp. 548–565.
Toms, J., Müller, T. M., Ciz, R., Gurevich, B.
(See online at https://dx.doi.org/10.1016/j.soildyn.2006.01.008) - Seismic attenuation due to wave-induced flow: Why Q in random structures scales differently. Geophysical Research Letters, Vol. 33. 2006, Issue 16, L16305.
Muller, T.M., Rothert, E.
(See online at https://dx.doi.org/10.1029/2006GL026789) - Dynamic permeability of porous rocks and its seismic signatures. Geophysics, Vol. 72. 2007, no. 5, p. E149-E158.
Muller, T. M., Lambert, G.P., Gurevich, B.
(See online at https://dx.doi.org/10.1190/1.2749571) - Fluid substitution, dispersion, and attenuation in fractured and porous reservoirs—insights from new rock physics models. The Leading Edge, Vol. 26 no. 9, pp. 1162-1168.
Gurevich, B., Galvin, R. J., Brajanovski, M.,, Muller, T. M., Lambert, G.
(See online at https://dx.doi.org/10.1190/1.2780787) - Seismic attenuation in porous rocks with random patchy Saturation.
Geophysical Prospecting, Vol. 55. 2007, Issue 5, pp. 671–678.
Toms, J., Müller, T. M., Gurevich, B.
(See online at https://dx.doi.org/10.1111/j.1365-2478.2007.00644.x) - Attenuation of seismic waves due to waveinduced flow and scattering in random porous media. In: Earth heterogeneity and scattering
effects on seismic waves, Eds. H. Sato, M. Fehler, Advances in Geophysics, Vol. 50. 2008, pp. 123-166, Elsevier.
Muller, T. M., Gurevich, B., Shapiro, S.A.
(See online at https://dx.doi.org/10.1016/S0065-2687(08)00005-8) - Modeling elastic and poroelastic wave propagation in complex geological Structures. In: High Performance Computing in Science and Engineering '07, Eds., W. E. Nagel, D. Kroner, M. Resch. Springer, 2008, pp 587-601.
F. Wenzlau, T. Xia, T. M. Muller
(See online at https://dx.doi.org/10.1007/978-3-540-74739-0_40) - Simulating 3-D seismograms in 2.5D heterogeneous structures by combining 2D nite-difference modelling and ray tracing.
Geophysical Journal International, Vol. 174. 2008, Issue 1, pp. 309-315.
Miksat, J., Müller, T. M., Wenzel, F.
(See online at https://dx.doi.org/10.1111/j.1365-246X.2008.03800.x) - Direct laboratory observation of patchy Saturation and its effects on ultrasonic velocities. The Leading Edge, vol. 28. 2009, Issue 1, pp. 24-27.
Lebedev, M., Toms-Stewart, J., Clennell, B., Pervukhina, M., Shulakova, V., Paterson, L., Müller, T.M., et al.
(See online at https://dx.doi.org/10.1190/1.3064142) - Green's functions and radiation patterns in poroelasticity revisited. Geophysical Journal International, Vol. 178.2009, Issue 1, pp. 327-337.
Karpfinger, F., Müller, T. M., Gurevich, B.
(See online at https://dx.doi.org/10.1111/j.1365-246X.2009.04116.x) - Microseismic signatures of non-linear pore-fluid pressure diffusion. Geophysical Journal International, Vol. 179. 2009, Issue 3, pp. 1558-1565.
Hummel, N., Müller, T. M.,
(See online at https://dx.doi.org/10.1111/j.1365-246X.2009.04373.x) - P-wave dispersion and attenuation in fractured and porous reservoirs { poroelasticity Approach. Geophysical Prospecting, Vol. 57. 2009, Issue 2, pp. 225–237.
Gurevich, B., Brajanovski, M., Galvin, R. J., Müller, T. M., Toms-Stewart, J.
(See online at https://dx.doi.org/10.1111/j.1365-2478.2009.00785.x) - Ansiotropic dispersion and attenuation due to wave-induced flow: quasi-static nite-element modeling in poroelastic solids. Journal
Geophysical Research (JGR):Solid Earth, Vol. 115. 2010, Issue B7, B07204.
Wenzlau, F., Altmann, J. B., Müller, T. M.
(See online at https://dx.doi.org/10.1029/2009JB006644) - Poroelastic contribution to the reservoir stress path. International Journal of Rock Mechanics and Mining Sciences, Vol. 47. 2010, Issue 7, pp. 1104–1113.
Altmann, J. B., Müller, T. M., Muller B. I. R., Tingay, M. R. P., Heidbach, O.
(See online at https://dx.doi.org/10.1016/j.ijrmms.2010.08.001) - Seismic wave attenuation and Dispersion resulting from wave-induced
flow in porous rocks - a review. Geophysics
Volume 75, Issue 5, pp. 75A147-75A164.
Müller, T. M., Gurevich, B., Lebedev, M.
(See online at https://dx.doi.org/10.1190/1.3463417) - Anisotropic P-SV-wave dispersion and attenuation due to inter-layer
flow in thinly layered porous rocks. Geophysics, vol. 76.2011, pp. WA135-WA145.
Krzikalla F., Müller, T.M.
(See online at https://dx.doi.org/10.1190/1.3555077) - Fast compressional wave attenuation and dispersion due to conversion scattering into slow shear waves in randomly heterogeneous porous media. Journal of the Acoustical Society of America, Vol. 129. 2011, Issue 5, pp. 2785-2796.
Müller, T. M., Sahay, P. N.
(See online at https://dx.doi.org/10.1121/1.3560918) - Porous medium acoustics of wave-induced vorticity diffusion.
Applied Physics Letters, Vol. 98. 2011, Issue 8, 084101.
Müller, T. M., Sahay, P. N.
(See online at https://dx.doi.org/10.1063/1.3558721)
