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.
Figure 2.
Example of reconstructed
basin
geometry using 2D listric fault model (left) and
a simple 1D method (middle). The temperature difference between the two methods
is in this example close to 100°C (yellow color; right figure)
AAPG Search and Discover Article #90066©2007 AAPG Hedberg Conference, The Hague, The Netherlands