Least-squares reverse time migration with local Radon-based preconditioning
Type
ArticleKAUST Department
Center for Subsurface Imaging and Fluid ModelingEarth Science and Engineering Program
Physical Science and Engineering (PSE) Division
Date
2017-03-08Online Publication Date
2017-03-08Print Publication Date
2017-03Permanent link to this record
http://hdl.handle.net/10754/623005
Metadata
Show full item recordAbstract
Least-squares migration (LSM) can produce images with better balanced amplitudes and fewer artifacts than standard migration. The conventional objective function used for LSM minimizes the L2-norm of the data residual between the predicted and the observed data. However, for field-data applications in which the recorded data are noisy and undersampled, the conventional formulation of LSM fails to provide the desired uplift in the quality of the inverted image. We have developed a leastsquares reverse time migration (LSRTM) method using local Radon-based preconditioning to overcome the low signal-tonoise ratio (S/N) problem of noisy or severely undersampled data. A high-resolution local Radon transform of the reflectivity is used, and sparseness constraints are imposed on the inverted reflectivity in the local Radon domain. The sparseness constraint is that the inverted reflectivity is sparse in the Radon domain and each location of the subsurface is represented by a limited number of geologic dips. The forward and the inverse mapping of the reflectivity to the local Radon domain and vice versa is done through 3D Fourier-based discrete Radon transform operators. The weights for the preconditioning are chosen to be varying locally based on the relative amplitudes of the local dips or assigned using quantile measures. Numerical tests on synthetic and field data validate the effectiveness of our approach in producing images with good S/N and fewer aliasing artifacts when compared with standard RTM or standard LSRTM.Citation
Dutta G, Giboli M, Agut C, Williamson P, Schuster GT (2017) Least-squares reverse time migration with local Radon-based preconditioning. GEOPHYSICS 82: S75–S84. Available: http://dx.doi.org/10.1190/GEO2016-0117.1.Sponsors
G. Dutta would like to thank King Abdullah University of Science and Technology (KAUST) for funding his graduate studies. The authors are grateful to TOTAL E&P France for permission to publish this work. We also thank the associate editor K. Innanen and the three anonymous reviewers for their helpful comments and suggestions. The plots for this paper have been prepared using the Madagascar open-source software package.Publisher
Society of Exploration GeophysicistsJournal
GEOPHYSICSAdditional Links
http://library.seg.org/doi/abs/10.1190/geo2016-0117.1ae974a485f413a2113503eed53cd6c53
10.1190/GEO2016-0117.1