Direct statics estimation from ground-roll data

Direct statics estimation from ground-roll data

Bamarouf, T.

Draganov, D. (mentor)
Valentina Socco, L. (mentor)

Civil Engineering and Geosciences

Geoscience & Engineering

2016-08-12

• Statics correction can be computed by inverting the dispersion curves of surface waves (groundroll). • Inversion results generally require intensive processing and are affected by solution nonuniqueness. Here, we directly estimate the statics correction from the dispersion curves of surface waves, without the need for inverting the data. This can be achieved by finding the relationship between the time average S-wave velocity at different depths and the surface-wave phase velocity at different wavelengths. The same approach is found for the estimation of weighted average Pwave velocity, by exploiting the sensitivity of the wavelength/depth relationship to Poisson’s ratio. Prior information of the S-wave velocity profile corresponding to only one of the dispersion curves available in the area is required. We show on a synthetic dataset the possibility of extending this method to higher modes of surface waves. In case of a narrow frequency band, higher modes can investigate deeper; however, the fundamental mode showed better estimation of the near-surface corrections in a broader frequency band. We show the successful application of this method on an oil and gas exploration dataset in a sand dune area. By having only the ground roll in the data and a single profile of VS, we directly estimate the P- and S-wave statics correction. A comparable analysis between fundamental and higher modes of ground roll for the estimation of statics correction showed that using higher modes has the least error estimation, when compared to fundamental mode, in unconsolidated granular environment.

Higher modes
statics
ground-roll
near surface
Rayleigh waves

http://resolver.tudelft.nl/uuid:0ced7c24-50e2-4101-8474-382bda41195c

Student theses

master thesis

(c) 2016 Bamarouf, T.