The Stressful Life of Faults and Fractures - Numerical Models of Northeast Atlantic Stress and Paleostress

Faults and fractures play a key role in our understanding of petroleum systems. Basins geometries is in itself an issue of forces over time, but tectonic and gravitational forces also guide hydrocarbon migration and in some cases create or enhance reservoir properties in otherwise tight rocks. The fluid control of faults and fractures in part relates to lithology (e.g. clay smear) but is also closely linked to the stress history of a given structure. Fractures are likely acting as conduits if they are opening or critically stressed. The latter depends on the overall orientation of the stress field, fluid pressure, and to a lesser degree lithology. We present 4D (3D and time) models of kinematics, gravitational and tectonics forces from a inter-continental to a local (play)-scale across giant oil-fields, and demonstrate that we can duplicate measured values, but also extrapolate these data in time and space. For exaple we can show how stresses reverse from extensional to compressional over short distances due to basement topgraphy. These tectonic and gravitational stresses influence fracture aperture, and thus migration routes and reservoir potential, that some of these fields ultimetely depend on.