GEOPRESSURE EVOLUTION, HYDROCARBON GENERATION AND MIGRATION IN THE BEAUFORT-MACKENZIE BASIN, CANADA - RESULTS FROM 2-DIMENSIONAL QUANTITATIVE MODELING

Three cross-sections of onshore and offshore areas of the Beaufort-MacKenzie Basin were used to simulate geopressure evolution, hydrocarbon generation and migration processes of the Tertiary section using a two-dimensional model. Two analytical approaches were used: (1) adjusting geological, geophysical and geochemical parameters to obtain the best fit between the model results and regional geological data in a one-dimensional manner; and (2) reconstructing the basin evolutionary history in a two-dimensional manner. The model results indicate that the present day distributions of geopressure and maturity levels at different locations have been modified by late Miocene uplift and erosion, followed by rapid deposition of the late Miocene-Pleistocene Iperk sediments. Although the occurrence of oil and gas has no obvious relationship to geopressure at the present day, the evolution of geopressure in strata older than the Mackenzie sequence plays an important part in the maturation of Tertiary source rocks. Geopressure in these older formations caused an increase in thermal gradient and porosity in the deep formations. The analysis indicates that the timing of hydrocarbon generation and the evolution of geopressure are critical factors in the development of horizontal migration (Reindeer reservoirs) versus vertical migration (Kugmallit reservoirs).