Mar 22nd-West Side Tech Breakfast: Migration Velocity Analysis and Waveform Inversion with Subsurface Offset Extension*

May 11th - West Side Tech Breakfast
Sponsored by Schlumberger
Meeting Location:
Schlumberger Facility
10001 Richmond Ave.
Houston, TX  77042

Speaker: Dr. Lei Fu, Forland Geophysical Services

Image-domain seismic inversion with subsurface offset extension may converge to kinematically accurate velocity models without the low-frequency data accuracy required for standard data-domain full waveform inversion. However, this robust alternative approach to waveform inversion suffers from very high computational cost, resulting from its use of nonlocal wave physics: the computation of strain from stress involves an integral over the subsurface offset axis, which must be performed at every space-time grid point. Additionally, under prototypical conditions of acquisition geometry, the existence of artefacts is very likely to deviate the velocity update from its path to the correct velocity. I show here three new approaches that significantly improve both efficiency and robustness of subsurface offset extended waveform inversion and migration velocity analysis (MVA). The global convergence property of the extended waveform inversion is achieved by adaptively determining the penalty weight. It is also shown that a combination of data-fit driven offset limits, grid coarsening, and low-pass data filtering can reduce the cost of extended inversion by one to two orders of magnitude. Lastly, a taper in angle domain depending on acquisition geometry and imaging point is introduced. The application of taper directly on extended image makes migration velocity analysis becomes more robust. I illustrate these new methods in the context of constant density acoustic waveform inversion, by recovering background model and perturbation fitting band-limited waveform data in the Born approximation.

Speaker Biography: Dr. Lei Fu, Forland Geophysical Services
Lei Fu is Project Lead of Development & Imaging at Forland Geophysical Services. Lei studied seismic imaging and waveform inversion at Rice University (Ph.D., 2016), under the supervision of Prof. William Symes. He received his M.Sc. from University of Utah, where he developed a keen interest in geoscience. In addition to his expertise in exploration seismology, Lei has broad interests in geology, High-performance computing, machine learning, etc. In his free time, Lei enjoys hiking and road trips with his family.

Breakfast will be available starting at 7:00 AM
Technical Talk will start at 7:30
Event will end by 8:30


3/22/2017 7:00 AM - 8:30 AM

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