A recipe for practical full-waveform inversion in orthorhombic anisotropy
Type
Conference PaperKAUST Department
Earth Science and Engineering ProgramPhysical Science and Engineering (PSE) Division
Seismic Wave Analysis Group
Date
2016-09Online Publication Date
2016-09Print Publication Date
2016-09Permanent link to this record
http://hdl.handle.net/10754/625245
Metadata
Show full item recordAbstract
Multi parameter full waveform inversion (FWI) usually suffers from the inherent tradeoffin the multi parameter nature of the model space. In orthorhombic anisotropy, such tradeoffis magnified by the large number of parameters involved in representing the elastic or even the acoustic approximation of such a medium. However, using a new parameterization with distinctive scattering features, we can condition FWI to invert for the parameters the data are sensitive to at different stages, scales, and locations in the model. Specifically, with a combination made up of a velocity and particular dimensionless ratios of the elastic coefficients, the scattering potential of the anisotropic parameters have stationary scattering radiation patterns as a function of the type of anisotropy. With our new parametrization, the data is mainly sensitive to the scattering potential of 4 parameters: the horizontal velocity in the x direction, x, which provides scattering mainly near zero offset in the x vertical plane, εd, which is the ratio of the horizontal velocity squared in the x and x direction, and δ3 describing the anellipticity in the horizontal plane. Since, with this parametrization, the radiation pattern for the horizontal velocity and ε is azimuth independent, we can perform an initial VTI inversion for these two parameters, and then use the other two parameters to fit the azimuth variation in the data. This can be done at the reservoir level or any region of the model. Including the transmission from reflections, the migration velocity analysis (MVA) component, into the picture, the multi azimuth surface seismic data are mainly sensitive to the long wavelength components of uh, δ3, and εd through the diving waves, and η1, ηd, and δ3, in the transmission to or from reflectors (especially, in the presence of large offsets). They are also sensitive to the short wavelength component of uh and ε.Citation
Alkhalifah T, Masmoudi N, Oh J-W (2016) A recipe for practical full-waveform inversion in orthorhombic anisotropy. SEG Technical Program Expanded Abstracts 2016. Available: http://dx.doi.org/10.1190/segam2016-13844429.1.Publisher
Society of Exploration GeophysicistsConference/Event name
SEG International Exposition and 86th Annual Meeting, SEG 2016Additional Links
http://library.seg.org/doi/10.1190/segam2016-13844429.1ae974a485f413a2113503eed53cd6c53
10.1190/segam2016-13844429.1