Quantitative basin evaluation becomes a fundamental requirement of petroleum exploration, and it includes estimating the timing and amount of petroleum generation and migration. To understand a regional petroleum geology, all geological processes must be related one to another, and the information from each process must be integrated in a systematic manner. Simulation modeling is a very useful method to execute such process of thinking. A deductive forward model for this purpose was set up to simulate fluid flow compaction, heat transfer, maturation of organic matter, and hydrocarbon generation. This paper introduces basic theoretical aspects of the model.
The model, then, was applied to one of the oil field in the Niigata basin where a downward migration has been implied from the Nanatani mudstone to the lowest member Green Tuff. Through an application, the model reveals that the downward migration has occurred through most of the geologic time mainly because of capillary effects rather than regional hydrodynanic pressure gradients. For the shallower turbidite reservoirs, the model experiments indicate that the sandstone geometry is very sensitive for the hydrocarbon migration path ways. This suggests that capillary effects again play a significant role for a local migration pattern. The geologic data should be re-examined for the above hypothetical capillary effects on hydrocarbon migration.