Wave guiding in fractured layered media
Published:January 01, 2015
S. Shao, C. L. Petrovitch, L. J. Pyrak-Nolte, 2015. "Wave guiding in fractured layered media", Fundamental Controls on Fluid Flow in Carbonates: Current Workflows to Emerging Technologies, S. M. Agar, S. Geiger
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Many carbonate rocks are composed of layers and contain fracture sets that cause the hydraulic, mechanical and seismic properties to be anisotropic. Co-located fractures and layers in carbonate rock lead to competing wave-scattering mechanisms: both layers and parallel fractures generate compressional-wave (P-wave) guided modes. The guided modes generated by the fractures may obscure the presence of the layers. In this study, we examine compressional-wave guided modes for two cases: wave guiding by fractures in a layered medium with sub-wavelength layer thickness; and wave guiding in media with competing scattering mechanisms, namely layering (where the thickness is greater than a wavelength) and parallel sets of fractures. In both cases, the fracture spacing is greater than a wavelength. When the layer thickness is smaller than a wavelength, P-wave guiding is controlled by the spacing of the fractures, fracture specific stiffness, the frequency of the signal and the orientation of the layering relative to the fracture set. The orientation of the layering determines the directionally dependent P-wave velocity in the anisotropic matrix. When the layer thickness is greater than a wavelength and an explosive point source of a signal is located in the layer containing a fracture, the fracture either enhanced or suppressed compressional-mode wave guiding caused by the layering in the matrix.
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Fundamental Controls on Fluid Flow in Carbonates: Current Workflows to Emerging Technologies
This volume highlights key challenges for fluid-flow prediction in carbonate reservoirs, the approaches currently employed to address these challenges and developments in fundamental science and technology. The papers span methods and case studies that highlight workflows and emerging technologies in the fields of geology, geophysics, petrophysics, reservoir modelling and computer science. Topics include: detailed pore-scale studies that explore fundamental processes and applications of imaging and flow modelling at the pore scale; case studies of diagenetic processes with complementary perspectives from reactive transport modelling; novel methods for rock typing; petrophysical studies that investigate the impact of diagenesis and fault-rock properties on acoustic signatures; mechanical modelling and seismic imaging of faults in carbonate rocks; modelling geological influences on seismic anisotropy; novel approaches to geological modelling; methods to represent key geological details in reservoir simulations and advances in computer visualization, analytics and interactions for geoscience and engineering.