Fault analysis of a salt minibasin offshore Espírito Santo, SE Brazil: Implications for fluid flow, carbon and energy storage in regions dominated by salt tectonics

Zhang, Qiang, Alves, Tiago M. ORCID: https://orcid.org/0000-0002-2765-3760 and Martins-Ferreira, Marco Antonio Caçador 2022. Fault analysis of a salt minibasin offshore Espírito Santo, SE Brazil: Implications for fluid flow, carbon and energy storage in regions dominated by salt tectonics. Marine and Petroleum Geology 143 , 105805. 10.1016/j.marpetgeo.2022.105805

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Abstract

High-quality 3D seismic reflection and well data are used to investigate the distribution, evolution history and significance of tectonic faulting in a salt minibasin offshore Espírito Santo, SE Brazil. Displacement-length (Dmax-L) plots, displacement-depth (D-Z) plots and structural maps are compiled to understand the growth history of distinct fault families. Interpreted structures include crestal, corridor, listric and keystone faults. Their geometry, orientation and relative distribution reveal important differences. In detail, listric faults were formed in the investigated salt withdrawal basin, following a NW- to WNW strike, with multiple bright spots and pockmarks around them. The strata into which listric faults sole out have similar seismic, lithological and petrophysical characters to known Cenomanian to Turonian source rocks, which comprise shales and marls with high gamma-ray values. Low-amplitude to transparent seismic facies further indicate the presence of ductile, highly likely organic-rich shales and marls. As a result, three evolutionary stages can be identified: a) Stage 1 is characterised by the formation of NW or WNW-striking listric faults, keystone faults and the onset of reactive diapirism; b) Stages 2 and 3 record active diapirism due to a relative increase in sediment loading, documenting the formation of many crestal, corridor and keystone faults. Importantly, normalised leakage factor analyses reveal keystone faults are the most favourable paths to fluid migrating in the investigated salt minibasin. Conversely, listric faults are likely to form barriers and baffles to fluid in their lower parts.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/, Start Date: 2022-06-17
Publisher:	Elsevier
ISSN:	0264-8172
Date of First Compliant Deposit:	1 July 2022
Date of Acceptance:	13 June 2022
Last Modified:	12 May 2023 00:43
URI:	https://orca.cardiff.ac.uk/id/eprint/150938

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