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

Figure 6

Fluid pressure (in color) and fracturing (in black) for scenario 3 with fluid pressure increase in a horizontal layer that is faulted in (b) and (c). A horizontal layer shows a fracture evolution that is similar to scenario 2 with a semihorizontal branching fracture in the layer. Once the layer is faulted, the fluid pressure gradients curve and form vertical to conjugate shear fractures at the layer tips where the fault is positioned. Fracturing within the layer is also more complicated because the layer is dilating in two dimensions in the vertical as well as the horizontal direction. This leads to stronger brecciation of the layer.