“Basin scale” versus “localized” pore pressure/stress coupling – Implications for trap integrity evaluation

Anatomy of a fluid pipe in the Norway Basin: Initiation, propagation and 3D shape

“…8b and c) that started to open in mixed mode, i.e. tensile-shear (Mourgues et al, 2011). This phenomenon is observed in all our experiments at the same critical depth (10 to 12 cm below the sand surface in the box) and is also described in most models of shallow intrusions (Mathieu et al, 2008;Galland et al, 2009).…”

“…Mourgues and Cobbold (2003) demonstrated that the use of air was suitable to simulate the effect of pore pressure and seepage forces and to control precisely effective stress fields in analogue models. Rodrigues et al (2009) discussed the use of air as a pore fluid to simulate sandstone intrusions and Mourgues et al (2011) verified analytical predictions on fracturing pressure with similar experiments. Moreover, most of the powders having cohesion in dry environments lose their cohesive properties when they are saturated with water.…”

“…We filled the models with diatomite powder characterized by high porosity (70%) and low density (300 kg/m 3 ). The pure powder has a measured tensile strength of 80 Pa (Mourgues et al, 2011). Gray scale images were captured at 100 frames per second and were used to calculate displacements and deformations by a Particle Imaging Velocimetry (PIV) technique.…”

Seismic-scale funnel-shaped collapse features from the Paleocene–Eocene of the North West Shelf of Australia

“…The shape of the funnels suggests that conical failure of the overburden took place at a level obeying the same mechanical rules as in conical intrusions (Mourgues et al, 2011). The hypothesis made here is that the corresponding (conical) fractures then acted as conduits for gas migration, so that gas eventually froze into hydrates following the conical path and impregnating sediment surrounding the failure surface(s).…”

“…The resulting pressure ruptures the overburden in the same way as sand or magma intrusions do when they reach a critical depth, as shown by Mourgues et al (2011) from analog experiments. • The failure of the overburden along a cone favors gas migration along this cone, just like the intrusion of sand slurry in the case of conical sand intrusions.…”