Shona M. Ness¹, I. Hutcheon¹
(1) University of Calgary, Calgary, AB

Abstract: The application of basin analysis to the Triassic Succession in the Alberta Basin, Canada

Triassic hydrocarbons are a primary exploration target in the Alberta Basin. Several oils and natural gas accumulations have been correlated to sources within, and immediately overlying, the Triassic section. Yet, the timing of generation, expulsion, and migration are poorly understood. Basin analysis is utilized to place limits on these processes and, in so doing, provide constraints on the burial and thermal history in the study area.

The model is constructed with current geological knowledge and a reasonable geothermal regime and then calibrated against various thermal and maturity indicators. Sensitivity analysis demonstrates that the model is most sensitive to the amount and lithology of sediment eroded following the Laramide orogeny and secondarily to the thermal regime. Also, the appropriate choice of calculations used to simulate porosity and permeability evolution, heat transfer and maturation is significant.

One-dimensional analysis indicates that the amount of sediment eroded since the Eocene progressively increases from 1.2 to 3 kilometres nearing the Cordilleran deformation front. The thermal regime is variable, but generally increases to the southwest, though more so presently than at the time of maximum burial. Hydrocarbons were generated from Mid-Cretaceous in the Deep Basin to late Paleocene at intermediate depths and subsequently expelled during rapid burial. Modeling also suggests that temperatures were sufficient for secondary gas generation near the edge of the deformation front. Kinks in vitrinite reflectance data, used to constrain Deep Basin models, have implications for heat and fluid transfer. On-going two-dimensional basin analysis will help to constrain migration and fluid transport processes.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana