New Findings with Respect to Key Conditions Controlling the Jurassic-Cretaceous Petroleum System, Dutch Central Graben

摘要

This paper presents selected results from the analysis of the Jurassic-Cretaceous petroleum system in the Dutch Central Graben, with special focus on the Posidonia-Chalk oil system. In the analysis we used new tectonic heat flow reconstructions and newly compiled Cenozoic sediment water interface temperatures as well as recently interpreted pore pressure and leak-off pressure distributions in combination with the latest results of TNO s detailed geological mapping programme. 1D and 3D petroleum systems modelling in the Dutch Central Graben revealed a large variation in burial history of the Posidonia Shale Formation, resulting in very different temperatures, maturities and hydrocarbon generation histories, depending on structural position. An important part of the Posidonia source rock already started generating hydrocarbons in Cretaceous times, generation rates reaching their maximum values before the Late Cretaceous inversion of the graben. Depending on structural position, the Posidonia source rock also generated hydrocarbons during Paleogene and, in selected areas, in Neogene times. Hydrodynamic analysis, including basin modelling, showed that fluid overpressures in the Chalk reach high values in Quaternary times approaching measured leak-off pressures in the Dutch Central Graben, thus influencing late hydrocarbon charging and preservation conditions in the Chalk.