Palaeostress state around a rising salt diapir inferred from seismic reflection data

Zhang, Qiang and Alves, Tiago ORCID: https://orcid.org/0000-0002-2765-3760 2023. Palaeostress state around a rising salt diapir inferred from seismic reflection data. Marine and Petroleum Geology 155 , 106385. 10.1016/j.marpetgeo.2023.106385

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Abstract

A 3D seismic volume and borehole data from the Dutch North Sea are used to investigate the palaeostress state around a rising salt diapir. The results show radial, polygonal and keystone faults around the diapir of interest, which are separated into eight zones based on their geometry, strike and overall distribution. Principal fault families include: a) 400–3500 m long radial faults developed in flanking and corner areas of the salt diapir, and known to have accommodated the stretching resulting from its rise, b) 200–1500 m long polygonal faults providing a record of the stress conditions farther from radial faults, and c) 1000–1800 m long keystone faults controlled by the rise of a buried salt pillow during Paleogene tectonic inversion. Stress inversions for 10,401 interpreted faults reveal that the maximum principal palaeostress (σ1) is close to vertical, whereas intermediate and minimum principal palaeostresses (σ2 and σ3) are sub-horizontal, though variable in their magnitudes and orientations. Palaeostresses in flanking zones of the salt diapir show marked differences when compared with corner zones, but the combination of minimum principal palaeostresses from all flanking and corner zones formed a triangular stress ring around the salt diapir. Importantly, the width of this stress ring was not only associated with the rise of the salt diapir, but also largely influenced by adjacent salt structures. Additionally, minimum principal palaeostresses estimated from polygonal fault systems are nearly normal to the boundary between polygonal and radial faults, implying that the rise of the salt diapir influenced the stress field in the outer part of its flanks. Stress inversion is shown here as a key method to understand the palaeostress state around the salt diapirs with triangular geometry and multiple growth stages, providing insights into their evolving stress states. This work also has implications to the analysis of salt diapirs, and their adjacent strata, in areas posed for carbon sequestration, gas storage, and the production of oil and gas.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Publisher:	Elsevier
ISSN:	0264-8172
Date of First Compliant Deposit:	7 July 2023
Date of Acceptance:	19 June 2023
Last Modified:	22 Aug 2023 18:19
URI:	https://orca.cardiff.ac.uk/id/eprint/160849

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