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Center for Wave Phenomena Department of Geophysics Colorado School of Mines Golden, Colorado. CWP Faculty. Ilya Tsvankin. Ilya Tsvankin. Roel Snieder. Dave Hale. Paul Sava. Norm Bleistein. Ken Larner. “We are committed to quality education.”. What do we offer?. Full financial support
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Center for Wave Phenomena Department of GeophysicsColorado School of MinesGolden, Colorado
CWP Faculty Ilya Tsvankin Ilya Tsvankin Roel Snieder Dave Hale Paul Sava Norm Bleistein Ken Larner “We are committed to quality education.”
What do we offer? • Full financial support • Diverse and enthusiastic faculty • State-of-the-art research • Industry contacts and internships
Need more Information? Prof. Ilya Tsvankinilya@dix.mines.edu Prof. Roel Sniederrsnieder@mines.edu www.cwp.mines.edu Center for Wave PhenomenaColorado School of MinesGolden, CO 80401
Seismic interferometry:Who needs a seismic source? Roel Snieder email rsnieder@mines.edu
Problem with sub-salt imaging salt reservoir
What if we had virtual sources below the salt? salt reservoir
Response to random sources Correlation:
Very Long Baseline Interferometry http://www.lupus.gsfc.nasa.gov/brochure/bintro.html
Distance between USA and Germany http://www.lupus.gsfc.nasa.gov/brochure/btoday2.html
Cross-correlation • sum of causal and acausal response • uncorrelated left- and rightgoing waves
Need to extend this to include: • heterogeneous media • - more space dimensions
Derivation based on normal-modes (Lobkis and Weaver, JASA, 110, 3011-3017, 2001)
Displacement response Heaviside function
Correlation Green’s function
Correlation and Green’s function • sum of causal and acausal Green’s function • holds for arbitrary heterogeneity
Raindrop model • Sources can be: • real sources • secondary sources (scatterers)
Extract response by correlation Correlation:
Stationary phase regions “anti-Fresnel zones”
Stationary phase integration (Snieder, Phys. Rev. E, 69, 046610, 2004)
Computing synthetic seismograms (Van Manen et al., Phys. Rev. Lett., 94, 164301,2005)
Field example of virtual sources complicated overburden reservoir (Bakulin and Calvert, SEG expanded abstracts, 2477-2480, 2004)
Peace River 4D VSP Component used, along-the-well (450)
Image from virtual sources top bottom
Virtual source Surface
Surface waves (Campillo and Paul, Science, 299, 547-549, 2003)
correlation Green’s tensor Z/Z Z/R Z/T
Surface wave Green’s function (Snieder, Phys. Rev. E, 69, 046610, 2004)
Seismic interferometry in Millikan Library (Snieder and Safak, Bull. Seismol. Soc. Am., 96, 586-598, 2006)
normal modes traveling waves