ABSTRACT: Petroleum Generation Modeling with Kerogen Kinetics and Apatite Fission-Track Data

Peter C. Van De Kamp, P. Kamp, A. Samoun, P. Green

Kerogen kinetics parameters (activation energies and frequency factors) can now be determined at reasonable cost in a short time for virtually any source rock kerogen. The thermal histories of source rocks and the stratigraphic sequences in which they occur are now routinely studied by apatite fission track analysis (AFTA) to yield maximum burial temperature and the time of that heating. With these parameters available plus the appropriate geological data, it is possible to estimate, with a greater degree of accuracy than by other methods, the depth and timing of hydrocarbon generation and migration in sedimentary basins with commercially available software.

With these methods we have uniquely modelled the likely hydrocarbon generation and migration scenarios for the Otway basin of Australia, the Taranaki basin of New Zealand, and the Huntington Valley of Nevada with the timing of generation rigorously constrained by results of AFTA investigations.

In selected wells in the Otway basin, AFTA data are consistent with geological evidence that rocks throughout the section are currently at their maximum temperatures ever. For the southern Taranaki basin, AFTA, in four wells revealed varying amounts (1-3 km) of late Miocene uplift and erosion. With these observations, reconstructions have been made of thermal histories of potential source rocks in the Lower Cretaceous Otway Group and Late Cretaceous to early Tertiary coal measures in the Taranaki basin wells. In the Nevada example, generation in the Elko oil shale started 3-6 Ma and was 50% complete 0-2 Ma. This is a very young episode of generation and migration occurring after major trap-forming middle Tertiary tectonism and middle to late Tertiary burial.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990