Seismic Dispersion and Attenuation in Saturated Porous Rock With Aligned Slit Cracks
MetadataShow full item record
©2018. American Geophysical Union. All Rights Reserved. We estimate the seismic attenuation and velocity dispersion induced by fluid pressure diffusion in a saturated porous medium containing a sparse distribution of aligned slit fractures. This is done by solving the scattering problem for a single crack and using Waterman-Truell scattering approximation for a distribution of cracks. This approach gives a numerical solution for the entire frequency range and analytical solutions for the low- and high-frequency limits. Analysis of the results shows that the characteristics of the seismic dispersion and attenuation for the slit cracks are similar to known results for penny-shaped crack. At high frequencies, the attenuation and dispersion are controlled by the crack density regardless of the crack geometry. At low frequencies, due to the different geometries of the slit and penny-shaped cracks, the characteristics of seismic dispersion and attenuation are different. For both the slit and penny-shaped crack case, the slope of the frequency dependence attenuation of factor (inverse quality factor) Q-1 tends to be 1. Yet the low-frequency asymptotic solutions for these two cases are somewhat different. For penny-shaped cracks, the Q-1(?) on the bilogarithmic scale has a straight line asymptote with slope 1, so that the attenuation factor at low frequencies is proportional to the frequency ?. However, for slit cracks, the asymptotic low-frequency solution contains a logarithmic function of ?, and no such asymptote exists. At the same time, similarly to the penny-shaped crack case, the solution for compressional velocity in the low-frequency limit is consistent with the anisotropic Gassmann theory.
Showing items related by title, author, creator and subject.
Galvin, Robert (2007)Development of a hydrocarbon reservoir requires information about the type of fluid that saturates the pore space, and the permeability distribution that determines how the fluid can be extracted. The presence of fractures ...
Gurevich, Boris; Brajanovski, Miroslav; Galvin, R.; Muller, T.; Toms, Julianna (2009)Natural fractures in hydrocarbon reservoirs can cause significant seismic attenuation and dispersion due to wave induced fluid flow between pores and fractures. We present two theoretical models explicitly based on the ...
Theoretical and numerical modelling of the effect of viscous and viscoelastic fluids on elastic properties of saturated rocksMakarynska, Dina (2010)Rock physics is an essential link connecting seismic data to the properties of rocks and fluids in the subsurface. One of the most fundamental questions of rock physics is how to model the effects of pore fluids on rock ...