Influence of Structural Deformation on Temperature Distribution through Time

Fausto Mosca, Ana Krueger, and Ed Gilbert
Devon Energy, Houston, TX

The temperature regime of a basin is affected by many other geological processes throughout the history of the basin. These includes processes related to basin geometry (such as rifting processes), structural evolution of the basin (vertical and lateral translation of sediment masses during trap formation), deposition and erosion of sediments linked to intra-basin tectonism, physical processes related to compaction, as well as heat and fluid flow. Tectonism not only plays an important role by providing traps for hydrocarbon accumulations in the sedimentary basin, but the effects on the thermal regime, and consequently upon hydrocarbon maturation, can be significant. The challenge we have confronted in recent years was to reconstruct a realistic description of the evolving structural geometry over geological time with emphasis on lateral movements. At Devon we have developed work flows for combining tectonic modeling with sedimentological history and temperature history that profoundly affect hydrocarbon generation and migration. Two-dimensional fluid flow/compaction models not only allow for both conduction and convection of heat, but illustrate the effects of vertical and lateral movements of large sediment bodies, as well as their constantly changing geometry. Within individual basins there may be significant lateral temperature contrasts between sediment masses, and significant vertical or lateral movements will affect source rock maturity in both space and time. Thus the magnitude of thermal anomalies depends not only upon simple thickness (burial history), but upon the constantly evolving sediment body geometry. We conclude that the modeled results provide more accurate estimates of the influence of structures as effective oil generation/migration migration pathways from various source intervals.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece