An algorithm for full waveform inversion of vector acoustic data

Akrami, Seyed Mostafa (2017) An algorithm for full waveform inversion of vector acoustic data. Masters thesis, Memorial University of Newfoundland.

[English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (9MB)

Abstract

In exploration seismology, constructing an accurate velocity model is imperative. One of the algorithms which can lead to an accurate velocity model is Full Waveform Inversion (FWI). FWI takes advantage of full wave information that is, direct, reflection and refraction waveforms and tries to construct the model parameters that best fit the data and obtain the best-fit images of the Earth’s subsurface. Depending on the environment, these parameters could be compressional or shear wave velocities, density, Lame parameters, etc. Acoustic FWI uses only scalar data such as pressure to construct a velocity model and does not provide any directivity information about the wavefields. Mimicking the recent experiments in seismic acquisition, which allow for recording different types of data (scalar and vector data) in terms of FWI scheme is crucial for complex imaging problem. This is because, extending FWI to vector data allows us to use both pressure and velocity components at the same time, giving directivity information about the wavefields. By extending FWI to vector data and thus improving the input data to FWI, we obtain both improved resolution and directivity information. This can be done by employing monopole as well as dipole sources and regularized joint objective functions. I demonstrate my algorithm with four models.

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