Petroleum System Modeling for (Un)Conventional Hydrocarbon Resources Assessment The Broad Fourteens Basin, The Netherlands

Abdul Fattah, Rader ¹; Verweij, Hanneke ¹; ten Veen, Johan ¹; Witmans, Nora ¹
(1)TNO, Utrecht, Netherlands.

The Broad Fourteens Basin is a northwest-southeast trending structure in the Dutch part of the Southern North Sea area. The basin is one of the most prolific petroleum areas in the Dutch offshore. It was formed during the Mesozoic and it was subject to major inversion movements during the Late Cretaceous and Early Tertiary. Important commercial hydrocarbon accumulations have been found in the Upper Permian and Upper Jurassic formations. The reservoirs are charged from gas-prone Carboniferous and Jurassic oil-prone source rocks. The basin has been extensively studied since the first successful exploration well in 1968. There is a wide range of information and data available which allows better controls on the 3D models for the basin.

More detailed insight in the timing of hydrocarbon generation of the conventional petroleum systems is much needed as a basis to assess drainage areas of undiscovered prospects. In addition, there is a need for information on burial history, temperature and maturity history of the Jurassic and Carboniferous formations in order to evaluate their prospectivity as shale gas plays.

We use 3D basin modeling to analyze the evolution of the basin as well as the maturity of the main source rock units. For this purpose, we use the latest results of the mapping project of the Dutch offshore, including the newly constructed erosion scenarios and thicknesses. A detailed basal heat-flow study allow us to use heat-flow maps in our model which are derived from detailed tectonic modeling of the basin. In addition, new surface-water interface temperatures and paleo water depth data, based on recent geo-biological studies, are used for the upper boundary condition and the tectonic reconstruction. The models are calibrated to field data using the wealth of data available from the basin, including temperature and vitrinite reflectance measurements. This permits the evaluation of different geological scenarios that reflect the evolution of the basin.

Our models show that using detailed heat-flow models, based on tectonic analyses of the basin, provide a more realistic estimation of the maturity evolution of the petroleum systems in the basin. Moreover, the duration and intensity of major uplift and erosion events have significant impact on the maturity of the source rocks. The modeling has provided new ideas on the maturity of the source rocks in the basin which will aid exploration activities for new (un)conventional prospects.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.