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Automatic velocity analysis using bootstrapped differential semblance and global search methods  

Choi, Hyung-Wook (Department of Natural Resources and Environmental Engineering, Hanyang University)
Byun, Joong-Moo (Department of Natural Resources and Environmental Engineering, Hanyang University)
Seol, Soon-Jee (Department of Natural Resources and Environmental Engineering, Hanyang University)
Publication Information
Geophysics and Geophysical Exploration / v.13, no.1, 2010 , pp. 31-39 More about this Journal
Abstract
The goal of automatic velocity analysis is to extract accurate velocity from voluminous seismic data with efficiency. In this study, we developed an efficient automatic velocity analysis algorithm by using bootstrapped differential semblance (BDS) and Monte Carlo inversion. To estimate more accurate results from automatic velocity analysis, the algorithm we have developed uses BDS, which provides a higher velocity resolution than conventional semblance, as a coherency estimator. In addition, our proposed automatic velocity analysis module is performed with a conditional initial velocity determination step that leads to enhanced efficiency in running time of the module. A new optional root mean square (RMS) velocity constraint, which prevents picking false peaks, is used. The developed automatic velocity analysis module was tested on a synthetic dataset and a marine field dataset from the East Sea, Korea. The stacked sections made using velocity results from our algorithm showed coherent events and improved the quality of the normal moveout-correction result. Moreover, since our algorithm finds interval velocity ($\nu_{int}$) first with interval velocity constraints and then calculates a RMS velocity function from the interval velocity, we can estimate geologically reasonable interval velocities. Boundaries of interval velocities also match well with reflection events in the common midpoint stacked sections.
Keywords
automatic velocity analysis; bootstrapped differential semblance (BDS); interval velocity; Monte Carlo inversion; root mean square velocity constraint; RMS;
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