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Published January 2022 | Published
Journal Article Open

True-amplitude migration through regularized extended linearized waveform inversion

Abstract

The ability to create subsurface images whose amplitudes are proportional to the elastic wavefield variations recorded within seismic data as a function of reflection angle is fundamental for performing accurate amplitude-variation-with-offset (AVO) analysis and inversion. A process that generates such images is commonly referred to as true-amplitude migration. We have determined how the extended subsurface-offset image space is able to preserve the elastic behavior of the primary reflections when these events are acoustically migrated with a reverse time migration approach performed in a least-squares fashion. Using a single-interface model, we determine how the angle-domain image amplitude variations from an extended-offset acoustically migrated image closely follow the theoretical elastic Zoeppritz response even at the critical angle. Furthermore, we develop a subsalt synthetic test in which 1C ocean-bottom-node (OBN) data are used within a regularized linearized waveform inversion procedure. In this test, we highlight the ability of the acoustic extended-angle image domain to preserve the correct elastic amplitude variations of the reflected events from three subsalt sand lenses. Our method allows accurate inversion of elastic-wave data for subsurface parameter variations that are critical for reservoir characterization in oil and gas exploration and production. We determine its performance on an OBN field data set recorded in the Gulf of Mexico in which the AVO response of a potential gas-bearing prospect is correctly retrieved.

Additional Information

© 2022 Society of Exploration Geophysicists. Manuscript received by the Editor 9 February 2021; revised manuscript received 20 June 2021; published ahead of production 22 September 2021; published online 10 November 2021. E. Biondi and B. Biondi would like to thank the Stanford Exploration Project affiliate companies for their financial support. Also, we would like to thank G. Barnier for sharing his graphics processing unit-based wave-equation library that was used in this work. We also thank J. Stefani, D. Bevc, and J. Washbourne for fruitful discussions on the covered topic. M. Meadows was a member of the Center of Research Excellence (CoRE) when contributing to this paper; CoRE is a partnership between Chevron Energy Technology Company and Stanford University for the purpose of advancing knowledge and applications in the fields of reservoir imaging, reservoir characterization, and reservoir simulation. Finally, we would like to acknowledge Shell Exploration and Production Company for their permission to show the obtained results and for providing the described field data set. DATA AND MATERIALS AVAILABILITY. Data associated with this research are confidential and cannot be released.

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Additional details

Created:
August 22, 2023
Modified:
October 23, 2023