On the role of diffractions in velocity model building: a full-waveform inversion example

Sergius Dell, Ivan Abakumov, Pavel Znak, Dirk Gajewski, Boris Kashtan, Andrey Ponomarenko

Результат исследований: Научные публикации в периодических изданияхстатьярецензирование

Аннотация

Imaging of small-scale heterogeneities is important for the geological exploration in complex environments. It requires a processing sequence tuned to high-resolution model building. Conventional methods which use refractions or reflections might face problems in resolving small-scale features since they are visually close to the resolution of the reflection images. Additional information or an unconventional technology, which supports the reflection imaging, is thus of great interest. An unconventional method based on seismic diffractions naturally complements specular reflection imaging. Diffracted waves represent a direct seismic response from small-scale subsurface heterogeneities, such as inclusions with a characteristic size of the prevailing wavelength, or discontinuities in geological interfaces, such as faults and fractures. We investigate the rule of diffracted part of the wavefield on velocity model building using a full-waveform inversion (FWI) example. In order to best acknowledge refracted and reflected parts of the wavefield in FWI, we chose a synthetic data example which mimics the ocean-bottom nodes acquisition survey as it provides almost perfect conditions for FWI of diving waves, a standard tool for high-resolution model building. We show, that FWI using diving waves produces a well-resolved anomaly. Including other part of the wavefield, reflected waves, further improves the resolution of the velocity anomaly but also leads to a gentle overfitting due to missing illumination from the very steep anomaly flanks. Considering diffracted events in FWI improves the model resolution even further resulting in a detailed velocity model and correctly imaged anomaly in both vertical and lateral directions.
Язык оригиналаанглийский
Страницы (с-по)538-553
Число страниц16
ЖурналStudia Geophysica et Geodaetica
Том63
Номер выпуска4
Ранняя дата в режиме онлайн5 сен 2019
DOI
СостояниеОпубликовано - 1 окт 2019

Предметные области Scopus

  • Геохимия и петрология
  • Геофизика

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