Cooperative, Structural and Grid-based Simultaneous Joint Inversion for Salt Base and Presalt Imaging

Mantovani, M.; Hokstad, Ketil; Trezzi, Stefano; Navaza, M.L.; Duffaut, Kenneth; Wiik, Torgeir; Lovatini, A.; Guerra, I.

doi:10.3997/2214-4609.20141108

Cited by 3 publications

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“…Frequencies higher than 0.1 Hz are commonly unusable [21]. A possible approach to overcome this issue is to combine CSEM and MT to interpret using joint-inversion, clearer subsurface images [26,27].…”

Section: Sub-salt Imagingmentioning

confidence: 99%

Twenty Years of CSEM Exploration in the Brazilian Continental Margin

et al. 2023

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The controlled source electromagnetic (CSEM) method is frequently used as a risk reduction tool in hydrocarbon exploration. This paper aims to provide a comprehensive historical review of the CSEM method’s twenty-year history in the Brazilian continental margin. Since 2003, we have significantly improved our understanding of CSEM resistivity data across various geological scenarios. This review presents a roadmap of the technical advancements in acquisition design and interpretation techniques. As a result, our understanding of the methodology has broadened from traditional to more general use, such as salt imaging, gas hydrates, geohazard mapping, and reservoir characterization. Finally, we indicate the potential upcoming CSEM applications in new energy resources and carbon capture and storage.

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Section: Sub-salt Imagingmentioning

confidence: 99%

Twenty Years of CSEM Exploration in the Brazilian Continental Margin

et al. 2023

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Broadband marine controlled-source electromagnetic for subsalt and around salt exploration

Zerilli¹,

Buonora

Menezes

et al. 2016

Interpretation

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Salt basins, mainly Tertiary basins with mobilized salt, are notoriously difficult places to explore because of the traditionally poor seismic images typically obtained around and below salt bodies. In areas where the salt structures are extremely complex, the seismic signal-to-noise ratio may still be limited and, therefore, complicate the estimation of the velocity field variations that could be used to migrate the seismic data correctly and recover a good image suitable for prospect generation. We have evaluated the results of an integrated seismic-electromagnetic (EM) two-step interpretation workflow that we applied to a broadband marine controlled-source EM (mCSEM) research survey acquired over a selected ultra-deepwater area of Espirito Santo Basin, Brazil. The presence of shallow allochthonous salt structures makes around salt and subsalt seismic depth imaging remarkably challenging. To illustrate the proposed workflow, we have concentrated on a subdomain of the mCSEM data set, in which a shallow allochthonous salt body has been interpreted before. In the first step, we applied a 3D pixel-based inversion to the mCSEM data intending to recover the first guess of the geometry and resistivity of the salt body, but also the background resistivity. As a starting model, we used a resistivity mesh given by seismic interpretation and resistivity information provided by available nearby wells. Then, we applied a structure-based inversion to the mCSEM data, in which the retrieved model in step one was used as an input. The goal of that second inversion was to recover the base of the salt interface. The top of the salt and the background resistivities remained fixed throughout the process. As a result, we were able to define better the base of the allochthonous salt body. That was reinterpreted approximately 300–700 m shallower than interpreted from narrow azimuth seismic.

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Near-surface modeling: A multiphysics approach

Mantovani

2016

The Leading Edge

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With the growth in geographic scale of land seismic exploration, increasingly complex near-surface modeling capabilities are being employed for static corrections in data processing. Variations in subsurface properties can be detected by gravity and electromagnetic measurements. The principles of complementarity and of noncontradiction are employed to integrate the diverse sources of information in a cooperative or simultaneous joint inversion formalism. In common practice, geophysical methods are subject to equivalency in solution. Also, inversions of first breaks are based on the user's interpretation of early arrivals, and, therefore, they are exposed to systematic errors, especially if picking is automated as for large 3D data sets. In such circumstances, it is desirable to avoid overfitting of observations in inversion. Velocity models developed through a multiphysics approach do not suffer from velocity-depth ambiguity and provide a shallow model that is well protected from the influence of inaccuracy in seismic picking.

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Cooperative, Structural and Grid-based Simultaneous Joint Inversion for Salt Base and Presalt Imaging

Cited by 3 publications

References 0 publications

Twenty Years of CSEM Exploration in the Brazilian Continental Margin

Twenty Years of CSEM Exploration in the Brazilian Continental Margin

Broadband marine controlled-source electromagnetic for subsalt and around salt exploration

Near-surface modeling: A multiphysics approach

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