Bridging the Gap Between Basin Modeling and Structural Geology

W. Fjeldskaar
IRIS Research, Stavanger, Norway

Fairly simple exploration methods led to the early discoveries of the structural traps of oil and gas fields globally. A lot of interesting fields are, however, characterised by complicated geological structures. More sophisticated exploration methods are needed to make hydrocarbon discoveries in structural traps. There is therefore a growing need for basin modeling systems that can handle more of the complex controlling geological processes that lead to generation and migration of hydrocarbons. Better insight into the mechanisms of basin formation has a direct bearing on the predictive power of basin models. Figure 1 is an example of the coupling between the plate stress with basin modelling - the stress history may be important for understanding the mechanism and timing of domal structure development.

The most important factors behind the generation of hydrocarbons in sedimentary basins are temperature and time. The temperature regime in a basin is affected by various geological processes throughout the history of the basin. This includes processes related to basin geometry, such as basin formation, deposition/erosion of sediments and faulting, and physical processes related to compaction, heat flow and fluid flow.

In structurally complex basins we have found that it is important to represent the present geometry of the basin properly because this allows a realistic reconstruction of the basin geometry over geological time and more realistic calculations of the thermal evolution of the basin. Poor definition of the present and palaeo geometry of a basin can lead to large errors in the simulations of the temperature history and the hydrocarbon generation and migration. (Fig.2)

Figure 1. Modeled effect of extensional intra plate stress over a section from offshore mid Norway.