6 months at CWP: Done a lot, but not done yet Or: how to deal with black magic by Dr. Ernst...
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Transcript of 6 months at CWP: Done a lot, but not done yet Or: how to deal with black magic by Dr. Ernst...
6 months at CWP: Done a lot, but not done yet
Or: how to deal with black magic
by
Dr. Ernst Niederleithinger
Senior Scientist and Deputy Division Leader atBAM( Federal Institute for Materials Research and Testing)
Berlin, Germany
Visiting Research Professor at Colorado School of Mines
CWP Seminar, 2013-12-02 Niederleithinger 1
Motivation to come here:
But there was more than that!CWP Seminar, 2013-12-02 Niederleithinger 2
Content
Things to be cared about in geophysics and NDT:
Events
Changes
Images
Where to go from here?
CWP Seminar, 2013-12-02 Niederleithinger 3
Events
Seismics: Earthquakes, fracking,….
Concrete: Load induced cracks,…
Localization, Characterization
CWP Seminar, 2013-12-02 Niederleithinger 4
Events
One tool: Time Reversal (Fink et al.)
Reciprocity
Inject time reversed signals at receivers
Energy will focus at source
CWP Seminar, 2013-12-02 Niederleithinger 5
Events
One tool: Time Reversal (Fink et al.)
Reciprocity
Inject time reversed signals at receivers
Energy will focus at source
Improvement?Deconvolution!
CWP Seminar, 2013-12-02 Niederleithinger 6
Does it really work? Experiment!
CWP Seminar, 2013-12-02 Niederleithinger 7
Does it really work? Experiment!
CWP Seminar, 2013-12-02 Niederleithinger 8
Setup: forward
CWP Seminar, 2013-12-02 Niederleithinger 9
Data: forward
CWP Seminar, 2013-12-02 Niederleithinger 10
Setup: backwards
CWP Seminar, 2013-12-02 Niederleithinger 11
Data: backward
CWP Seminar, 2013-12-02 Niederleithinger 12
Focus!
CWP Seminar, 2013-12-02 Niederleithinger 13
Next topic: Changes
Seismics: stress, oil/gas content,….
Concrete: stress, degradation,….
Both: Detect it as early as possible!
„Global“ changes: Coda Wave Interferometry
Localization? Ideas by Pacheco & Snieder, Larose, Sens-Schönfelder,….
CWP Seminar, 2013-12-02 Niederleithinger 14
Simple experiments: subtle changes detected,but no localization!
CWP Seminar, 2013-12-02 Niederleithinger 15
Localization is possible!
CWP Seminar, 2013-12-02 Niederleithinger 16
Don’t believe it? Experiment!
CWP Seminar, 2013-12-02 Niederleithinger 17
Don’t believe it? Experiment!
CWP Seminar, 2013-12-02 Niederleithinger 18
Don’t believe it? Experiment!
CWP Seminar, 2013-12-02 Niederleithinger 19
Results (“simple” CWI)
CWP Seminar, 2013-12-02 Niederleithinger 20
Results (“simple” CWI)
CWP Seminar, 2013-12-02 Niederleithinger 21
Preliminary Results (“advanced” CWI)
CWP Seminar, 2013-12-02 Niederleithinger 22
Preliminary Results (“advanced” CWI)
CWP Seminar, 2013-12-02 Niederleithinger 23
Last but not least: Imaging
Seismics: Layers, structures, hydrocarbons
Concrete: rebars, tendons, voids, cracks,…
Both: Mapping (multiple) reflections recorded close to/at the surface to where they belong! Same math+physics!
CWP Seminar, 2013-12-02 Niederleithinger 24
RTM
Ultrasonic black magic in TV
CWP Seminar, 2013-12-02 Niederleithinger 25
SAFT imaging
Main contributors to SAFT: Langenberg, Mayer, Marklein,University of Kassel
Friese et al., SMT 2008
Synthetic aperture focusing technique
Family of methods
Constant and multi-offset data
Direct reflections only
Phase evaluation possible (Krause et al., SF&R 2008)
CWP Seminar, 2013-12-02 Niederleithinger 26
Reverse Time Migration!
Sabine Müller Ernst Niederleithinger Maria Grohmann Martin Krause
Thomas Bohlen Paul Sava
CWP Seminar, 2013-12-02 Niederleithinger 27
Synthetic example 1
RTM
Model used for simulating data
Velocity modelfor migration
RTM result
CWP Seminar, 2013-12-02 Niederleithinger 28
Off to Horstwalde
Foundation slab at our test site
CWP Seminar, 2013-12-02 Niederleithinger 29
Off to Horstwalde
CWP Seminar, 2013-12-02 Niederleithinger 30
Off to Horstwalde
CWP Seminar, 2013-12-02 Niederleithinger 31
Off to Horstwalde
Simulations
CWP Seminar, 2013-12-02 Niederleithinger 32
Off to Horstwalde
Real data
CWP Seminar, 2013-12-02 Niederleithinger 33
Back to the lab
Measurements:
• Polyamide block,(100*60*30 cm³)
• Point contact transducersin arrays of 4
• P, SHx, SHy
CWP Seminar, 2013-12-02 Niederleithinger 34
Back to the lab
CWP Seminar, 2013-12-02 Niederleithinger 35
Back to the lab
CWP Seminar, 2013-12-02 Niederleithinger 36
Seismic Interferometry
Seismic Interferometry
• Reconstruction of Greens functions
• Data, where you think you don‘t have data
• Gerald Schuster• Roel Snieder
• Kees Wapenaar
CWP Seminar, 2013-12-02 Niederleithinger 37
„Green‘s function retrieval“, „Seismic Interferometry“
Trace interpolation, synthetic example (44 sources)
Seismic Interferometry
CWP Seminar, 2013-12-02 Niederleithinger 38
„Green‘s function retrieval“, „Seismic Interferometry“
Trace interpolation, synthetic example (44 sources)
Seismic Interferometry
CWP Seminar, 2013-12-02 Niederleithinger 39
„Virtual Real Source“ (Behura, 2006)
synthetic example (11 sources)
Seismic Interferometry
CWP Seminar, 2013-12-02 Niederleithinger 40
Back to the lab
Just more black magic? Experiment!
(on the way)
CWP Seminar, 2013-12-02 Niederleithinger 41
That will be simple. Reality is much more complicated:
CWP Seminar, 2013-12-02 Niederleithinger 42
Let‘s steal anotherblack magic idea:
Autofocusing
CWP Seminar, 2013-12-02 Niederleithinger 43
Let‘s steal anotherblack magic idea:
Autofocusing
CWP Seminar, 2013-12-02 Niederleithinger 44