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The Seismic Wave Forward Modeling And Attribute Extraction Method Research In Azimuth Anisotropic Media

Posted on:2012-12-24Degree:MasterType:Thesis
Country:ChinaCandidate:J L HeFull Text:PDF
GTID:2120330338493443Subject:Earth Exploration and Information Technology
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Anisotropy research is one of the hot and difficult spots in the geophysical industry today. The factors that affect seismic anisotropy of the earth medium are diverse, this paper mainly discusses the anisotropy caused by fracture. The anisotropy caused by aligned cracks or fissures often called Extensive Dilatancy Anisotropy ( EDA) or azimuth anisotropy. The main features of wave propagation in EDA media are differences in propagation speed, amplitude, waveform of reflection and phase along different directions. This paper mainly studies the forward modeling in 3D azimuth anisotropic media and the attribute extraction method of anisotropic parameters, using the azimuth attribute differences of seismic wave while propagates through the azimuth anisotropic media.This paper firstly discusses the wave theory in azimuth anisotropic media and gives the quantitative relationship among the elastic parameters of azimuth anisotropic media, Ruger characterization parameter and the fracture parameters. Under the condition of the acoustic approximate assumption, based on the HTI media Christoffel Equation, deduced the 3D qP acoustic equation of azimuth anisotropic media, whose parameters are Ruger characterization. And based on the 3D acoustic equation of HTI media, studied the forward modeling and reverse time migration.In the aspect of forward modeling, in order to improve the precision of differential simulation and reduce numerical frequency dispersion, we deduced the ten-order finite-difference algorithm in this paper. For the boundary treatment, we use the perfectly matched layer absorbing boundary. Then through a series of models, we proved the accuracy of the results.In the aspect of attribute differences of anisotropic medium azimuth, the research was divided into two parts. The first part mainly discussed the amplitude and traveling time variation with the azimuth angle in the fixed offset. The second part mainly discussed the amplitude variation with the azimuth angle and incident angle, under the wide azimuth observation system.In the aspect of reverse-time migration imaging, the cross-correlation imaging conditions is used on the forward modeling wave field and the reverse-time extrapolating wave field.In this paper, the numerical simulation method is used to study azimuth attribute variation characteristics in azimuth anisotropic media for the first time, which can provide the theoretical methods and theoretical data for further attribute extraction research and the result of this paper can be extended in actual application.
Keywords/Search Tags:azimuthal anisotropy, high-order finite difference, reverse-time migration imaging, azimuth amplitude variation characteristics
PDF Full Text Request
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