Large-scale 3D inversion of Towed Streamer ElectroMagnetic data using the Gauss-Newton method

Abstract

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2017Large-scale 3D inversion of Towed Streamer ElectroMagnetic data using the Gauss-Newton methodAuthors: Jenny-Ann MalmbergJohan MattssonJenny-Ann MalmbergPGS and Johan MattssonPGShttps://doi.org/10.1190/segam2017-17673312.1 SectionsSupplemental MaterialAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract We present a newly developed 3D inversion code for Towed streamer EM data utilizing the Gauss-Newton method. The code is designed and implemented on a standard cluster of nodes to handle large-scale inversions of the order 25 million unknowns. The corresponding Jacobian matrix of about 2 Tb is split over the subscribed computational nodes in order to reduce the memory consumption on each node as well as to reduce the computational time. This enables the use of the full Gauss-Newton method on this amount of data. The forward modeling part is based on a parallelized integral equation formulation of the electric field. The forward and inversion grids cover the entire survey area including bathymetry and down to 5 km below the sea surface. The performance is demonstrated with an unconstrained anisotropic 3D inversion on Towed Steamer EM data over a survey area covering a total of 5206 sq. km, acquired in the Barents Sea in 2014. The survey consisted of 38 parallel acquisition lines with a spacing of 1.25 km and an average length of 115 km. The selected number of data observations for this case was 505820 with a total of 6 frequencies in the range from 0.2 to 2.2 Hz, 7226 shot points and 16 receiver offsets. The inversion grid consisted of 13 million cells and extended from the water column down to 5 km below the sea surface. The inversion ran 14 Gauss-Newton iterations and converged to a misfit of 3.7% with a geologically feasible anisotropic resistivity model. Presentation Date: Tuesday, September 26, 2017 Start Time: 3:05 PM Location: 362A Presentation Type: ORAL Keywords: inversion, modeling, 3D, CSEMPermalink: https://doi.org/10.1190/segam2017-17673312.1FiguresReferencesRelatedDetails SEG Technical Program Expanded Abstracts 2017ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2017 Pages: 6093 publication data© 2017 Published in electronic format with permission by the Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished Online: 17 Aug 2017 CITATION INFORMATION Jenny-Ann Malmberg and Johan Mattsson, (2017), "Large-scale 3D inversion of Towed Streamer ElectroMagnetic data using the Gauss-Newton method," SEG Technical Program Expanded Abstracts : 1142-1146. https://doi.org/10.1190/segam2017-17673312.1 Plain-Language Summary Keywordsinversionmodeling3DCSEMPDF DownloadLoading ...