Scattering of Seismic Waves from Arbitrary Viscoelastic-Isotropic and Anisotropic Structures with Applications to Data Modelling, FWI Sensitivities and Linearized AVO-AVAz Analysis

It is acknowledged that Full Waveform Inversion (FWI) techniques are sensitive to the set of model parameters that we choose for the minimization procedure. This model parametrization and sensitivity analysis for FWI has been extensively studied for acoustic and isotropic-elastic media. In order to obtain an accurate image of subsurface earth, it is necessary to include both anisotropy and attenuation in inversion procedures as subsurface materials are far from being isotropic or elastic. In this thesis, we formulate the sensitivity analysis for FWI in viscoelastic-isotropic/anisotropic media. To develop such analysis, we construct a framework based on the first order perturbation theory called the Born approximation to find the sensitivity of the FWI to isotropic, anelastic and anisotropic parameters. Sensitivities are, essentially, radiation patterns induced by scattering of the seismic waves from inclusions in medium properties in an isotropic background. Most importantly, we investigate the effect of the inhomogeneity angle which is unique to viscoelastic waves, on these radiation patterns (scattering potentials) and also on amplitude-variation-with-offset or azimuth (AVO/AVAz) analysis. By decomposition of the scattering potentials into isotropic, viscoelastic and anisotropic components, we specify the effects of anelasticity, inhomogeneity of wave and anisotropy on radiation patterns and the linearized AVO/AVAz equations. Moreover, we show how the obtained scattering potentials reduce to the linearized AVO/AVAz equations without using the solution of Zoeppritz equations. This analysis is the starting point for any FWI strategy in a complex media exhibiting both attenuation and anisotropy, as the scattering potentials that we obtained can be effectively implemented to choose a suitable model parametrization.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Discipline thesis:degree_discipline

Geology and Geophysics

Grantor dc:publisher.institution

Graduate Studies

Year dc:date.issued

2017

Author dc:creator

• Moradi, Shahpoor

Advisor dc:contributor.advisor

• Innanen, Kristopher A.

Committee members dc:contributor.committeemember

• Liu, Qinya
• Lamoureux, Michael
• Krebes, Edward S.
• Lines, Laurence R.

• Geophysics

Statement dc:rights

• University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.

Language dc:language.iso

eng

DOI

http://dx.doi.org/10.11575/PRISM/27711

OAI identifier oai:identifier

oai:ucalgary.scholaris.ca:11023/3879