Fracturing and Porosity Channeling in Fluid Overpressure Zones in the Shallow Earth’s Crust

Figure 4

Time evolution of scenarios 1 and 2 (Figure 3) with the fluid pressure color coded in the background and fractures in black. The fluid pressure is rescaled for each picture. Time is in days. (a) Scenario 1 builds fluid pressure up until a single semihorizontal wavy fracture develops across the model. Successive fractures progress downwards and merge with existing ones to form a breccia-like pattern. (b) Scenario 2 develops a first set of fractures early on at positions where the fluid pressure gradients are steep. The fractures then progress inwards until after 5000 hours, an internal fracture pattern develops that forms tree-like branches and breccias.

(a)

(b)