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Zhuozhou, China

Bi L.-F.,Wuhan University | Bi L.-F.,Shengli Geophysical Institute | Qian Z.-P.,Geophysical Research Center | Zhang F.,Imperial College London | And 3 more authors.
Applied Geophysics | Year: 2011

On the basis of Chapman's (2003) model, as the seismic wave incidences angles vary from 0° to 45° while propagating in anisotropic media (HTI), the slow S-wave will sufferred by serious attenuation and dispersion and is sensitive to fluid viscosity but the P- and fast S-waves don't. For slow S waves propagating normal to fractures, the amplitudes are strongly affected by pore fluid. So, the slow S-wave can be used to detect fractured reservoir fluid information when the P-wave response is insensitive to the fluid. In this paper, 3D3C seismic data from the Ken 71 area of Shengli Oilfield are processed and analyzed. The travel time and amplitude anomalies of slow S-waves are detected and correlated with well log data. The S-wave splitting in a water-bearing zone is higher than in an oil-bearing zone. Thus, the slow S-wave amplitude change is more significant in water-bearing zones than in oil-bearing zones. © 2011 Editorial Office of Applied Geophysics and Springer-Verlag Berlin Heidelberg.

Qian Z.-P.,Geophysical Research Center | Zhang S.-H.,Geophysical Research Center | Zhao B.,Geophysical Research Center | Lei N.,Geophysical Research Center | Li X.-Y.,British Geological Survey
Applied Geophysics | Year: 2012

This study focuses on the factors that may affect the feasibility of performing elliptical anisotropy analysis on azimuthal PP- and PS-wave data in HTI media, with the aim of using the modeling results as guidance in real seismic data application. Our results reveal that there is an offset limitation for both PP- and PS-waves in elliptical anisotropy fitting, and that PS-waves show a wider applicable offset range and larger observable azimuthal anisotropy than PP-waves. The major axis of the elliptical fit to the amplitudes of the R-component is perpendicular to the fracture strike, which is opposite to that in PP-wave analysis. The azimuthal interval travel time of PS-waves shows a nearly elliptical distribution and the major axis of the fit ellipse is perpendicular to the fracture strike, which is same as that in PP-wave analysis. For data within the applicable offset range, the anisotropic magnitude obtained from amplitude and travel time attributes of PP- and PS-waves exhibits a dependence on fracture density, and the major to minor axis ratio of the fit ellipse may be used to infer the relative distribution of fracture densities. © 2012 Editorial Office of Applied Geophysics and Springer-Verlag Berlin Heidelberg.

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