Subsurface fluid flow and its implications for seabed pockmarks and mud volcanoes: An approach of distinct element method (DEM)

Unit-pockmarks and their potential significance for predicting fluid flow

“…A couple of recent publications addressed aspects of these questions, including the formation of unit-pockmarks and improve our understanding of pockmarks. One of these (Bui et al, 2007) used the distinct element method (DEM) to calculate the distribution of near-surface stress fields induced in sediments during fluid flux. That study showed that the flux would move in highly focused conduits and that the overlying sediments would be strongly deformed.…”

“…According to both the capillary seal model by Cathles et al (2010), and the DEM of Bui et al (2007), there is very little reason to expect an extensive lateral root system below 'first-generation' normal-pockmarks. Both models predict that the roots are vertical rather than spread out laterally.…”

“…pore-water and gas seepage (Cathles et al, 2010). This inference is based on a combination of (i) laboratory studies and on modern detailed studies at pockmarks over the Troll field in the Norwegian Channel and elsewhere De Vries et al, 2007a, b;Judd and Hovland, 2007), (ii) observations made from fossilized seepage locations (Aiello, 2005;Campbell et al, 2002;De Boever et al, 2009), (iii) high-resolution 3D-studies of seep locations (Heggland, 1998;Schroot et al, 2005;Cartwright et al, 2007), (iv) partly based on studies of mud volcanoes (Hovland et al, 1997;Dimitrov, 2002;Foucher et al, 2009;Etiope et al, 2009); and partly based on theoretical modelling (Bui et al, 2007;Cathles et al, 2010). However, it is expected that the exact mechanisms and processes involved in pockmark maintenance, i.e., the continuous local removal of suspension sediments, cannot be established before extended detailed monitoring of pockmarks has been performed.…”

The morphologies and genesis of mega-pockmarks near the Xisha Uplift, South China Sea

“…However, the last two situations may also contribute to the special seismic reflections. According to both the DEM (distinct element method) of Bui et al (2007) and the capillary seal model by Cathles et al (2010), the fluids are apt to migrate vertically upward. The depositional boundary constitutes a lateral inhomogeneity in the permeability distribution, and will have low resistance against the migration of over-pressured fluids (Fig.…”