2D acoustic-elastic coupled waveform inversion in the Laplace domain

Handle URI:
http://hdl.handle.net/10754/561589
Title:
2D acoustic-elastic coupled waveform inversion in the Laplace domain
Authors:
Bae, Hoseuk; Shin, Changsoo; Cha, Youngho; Choi, Yun Seok; Min, Dongjoo
Abstract:
Although waveform inversion has been intensively studied in an effort to properly delineate the Earth's structures since the early 1980s, most of the time- and frequency-domain waveform inversion algorithms still have critical limitations in their applications to field data. This may be attributed to the highly non-linear objective function and the unreliable low-frequency components. To overcome the weaknesses of conventional waveform inversion algorithms, the acoustic Laplace-domain waveform inversion has been proposed. The Laplace-domain waveform inversion has been known to provide a long-wavelength velocity model even for field data, which may be because it employs the zero-frequency component of the damped wavefield and a well-behaved logarithmic objective function. However, its applications have been confined to 2D acoustic media.We extend the Laplace-domain waveform inversion algorithm to a 2D acoustic-elastic coupled medium, which is encountered in marine exploration environments. In 2D acoustic-elastic coupled media, the Laplace-domain pressures behave differently from those of 2D acoustic media, although the overall features are similar to each other. The main differences are that the pressure wavefields for acoustic-elastic coupled media show negative values even for simple geological structures unlike in acoustic media, when the Laplace damping constant is small and the water depth is shallow. The negative values may result from more complicated wave propagation in elastic media and at fluid-solid interfaces.Our Laplace-domain waveform inversion algorithm is also based on the finite-element method and logarithmic wavefields. To compute gradient direction, we apply the back-propagation technique. Under the assumption that density is fixed, P- and S-wave velocity models are inverted from the pressure data. We applied our inversion algorithm to the SEG/EAGE salt model and the numerical results showed that the Laplace-domain waveform inversion successfully recovers the long-wavelength structures of the P- and S-wave velocity models from the noise-free data. The models inverted by the Laplace-domain waveform inversion were able to be successfully used as initial models in the subsequent frequency-domain waveform inversion, which is performed to describe the short-wavelength structures of the true models. © 2010 European Association of Geoscientists & Engineers.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Publisher:
Wiley-Blackwell
Journal:
Geophysical Prospecting
Issue Date:
Apr-2010
DOI:
10.1111/j.1365-2478.2010.00879.x
Type:
Article
ISSN:
00168025
Sponsors:
This work was supported by the Brain Korea 21 project of the Ministry of Education. The authors would like to thank Total for their financial support to the Laplace-domain inversion project and permission to publish this paper.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorBae, Hoseuken
dc.contributor.authorShin, Changsooen
dc.contributor.authorCha, Younghoen
dc.contributor.authorChoi, Yun Seoken
dc.contributor.authorMin, Dongjooen
dc.date.accessioned2015-08-02T09:14:52Zen
dc.date.available2015-08-02T09:14:52Zen
dc.date.issued2010-04en
dc.identifier.issn00168025en
dc.identifier.doi10.1111/j.1365-2478.2010.00879.xen
dc.identifier.urihttp://hdl.handle.net/10754/561589en
dc.description.abstractAlthough waveform inversion has been intensively studied in an effort to properly delineate the Earth's structures since the early 1980s, most of the time- and frequency-domain waveform inversion algorithms still have critical limitations in their applications to field data. This may be attributed to the highly non-linear objective function and the unreliable low-frequency components. To overcome the weaknesses of conventional waveform inversion algorithms, the acoustic Laplace-domain waveform inversion has been proposed. The Laplace-domain waveform inversion has been known to provide a long-wavelength velocity model even for field data, which may be because it employs the zero-frequency component of the damped wavefield and a well-behaved logarithmic objective function. However, its applications have been confined to 2D acoustic media.We extend the Laplace-domain waveform inversion algorithm to a 2D acoustic-elastic coupled medium, which is encountered in marine exploration environments. In 2D acoustic-elastic coupled media, the Laplace-domain pressures behave differently from those of 2D acoustic media, although the overall features are similar to each other. The main differences are that the pressure wavefields for acoustic-elastic coupled media show negative values even for simple geological structures unlike in acoustic media, when the Laplace damping constant is small and the water depth is shallow. The negative values may result from more complicated wave propagation in elastic media and at fluid-solid interfaces.Our Laplace-domain waveform inversion algorithm is also based on the finite-element method and logarithmic wavefields. To compute gradient direction, we apply the back-propagation technique. Under the assumption that density is fixed, P- and S-wave velocity models are inverted from the pressure data. We applied our inversion algorithm to the SEG/EAGE salt model and the numerical results showed that the Laplace-domain waveform inversion successfully recovers the long-wavelength structures of the P- and S-wave velocity models from the noise-free data. The models inverted by the Laplace-domain waveform inversion were able to be successfully used as initial models in the subsequent frequency-domain waveform inversion, which is performed to describe the short-wavelength structures of the true models. © 2010 European Association of Geoscientists & Engineers.en
dc.description.sponsorshipThis work was supported by the Brain Korea 21 project of the Ministry of Education. The authors would like to thank Total for their financial support to the Laplace-domain inversion project and permission to publish this paper.en
dc.publisherWiley-Blackwellen
dc.subjectAcoustic-elastic coupled mediaen
dc.subjectFinite-element methoden
dc.subjectLaplace domainen
dc.subjectLong-wavelengthen
dc.subjectWaveform inversionen
dc.title2D acoustic-elastic coupled waveform inversion in the Laplace domainen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalGeophysical Prospectingen
dc.contributor.institutionDepartment of Energy Systems Engineering, Seoul National University, Seoul 151-742, South Koreaen
dc.contributor.institutionExxonMobil Upstream Research Company, 3120 Buffalo Speedway, Houston, TX 77098, United Statesen
kaust.authorChoi, Yun Seoken
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