Physical modelling of sub-salt gliding due to fluid overpressure in underlying sedimentary strata. (April 2016)

• Record Type: Journal Article
• Authors: Akrout, Dhaou; Cobbold, Peter R.; Ahmadi, Riadh; Mercier, Eric; Montacer, Mabrouk
• Is Part Of: Marine and petroleum geology. Volume 72(2016:Apr.)
• Page Start: 139
• Page End: 155
• Publication Date: 2016-04
• Subjects: Physical modelling -- Sub-salt gliding -- Fluid overpressure -- Gulf of Mexico -- Offshore Brazil; Submarine geology -- Periodicals; Petroleum -- Geology -- Periodicals; Géologie sous-marine -- Périodiques; Pétrole -- Géologie -- Périodiques; Petroleum -- Geology; Submarine geology; Periodicals; Electronic journals; 551.468
• DOI: 10.1016/j.marpetgeo.2016.01.019
• Languages: English
• ISSNs: 0264-8172

Abstract

Abstract: The Gulf of Mexico and the offshore Campos and Santos basins of Brazil provide good examples of sub-salt detachments, by shearing in the presence of overpressure. We have developed new physical models of such situations, including layers of ductile silicone putty, which simulated an evaporite, and fluid overpressure in porous brittle layers. We studied two configurations, in which the maximal overpressure was either beneath a single ductile layer of silicone (simulating salt), or between two such layers of silicone (simulating an evaporite sequence). The results of our analogue modelling showed that detachment faults appeared and persisted at the bases of the ductile layers, even though some ductile deformation occurred simultaneously within these layers. For models where maximal overpressure was between two ductile layers, detachment occurred mainly at the base of the upper silicone layer. On comparing our models with structures in the Gulf of Mexico or offshore Brazil, we find strong similarities, which lead us to suspect that detachment is indeed possible at the base of an evaporite sequence in nature. This conclusion has strong implications, not only for the understanding of petroleum systems, but also for better management of petroleum production in sedimentary basins.