Petroleum Geologische Kring – The Triassic Hydrocarbon Potential of the Northern Dutch Offshore

Download hier de presentatie gepresenteerd door EBN tijdens het seminar Petroleum Geologische Kring.

The Lower Triassic Main Buntsandstein Subgroup forms part of an established hydrocarbon play in the southern North Sea. Regionally widespread mixed aeolian and fluvial sediments of the Lower Volpriehausen and Detfurth Sandstone members form the main reservoir rock. It is generally perceived that reservoir presence and quality decrease towards the north and that the prospectivity of the Main Buntsandstein play in the northern Dutch offshore is therefore limited. Lack of access to mature source rocks and hydrocarbon charge from the underlying Carboniferous sediments as a result of thick Zechstein salt are often identified as additional risks for this play. Consequently, only few wells have tested Triassic reservoir and this part of the basin remains relatively under-explored.

A regional study using wells and seismic data from the northern Dutch offshore and surrounding territories indicates the presence of Triassic reservoir sandstones north of the main, well-understood fairway. Recent studies of the source rock potential in the northern Dutch territory suggest that source rocks of different ages are present in the study area, while the presence of salt windows and Tertiary dykes allow vertical hydrocarbon migration. A study on the sealing capacity of overlying claystones and Röt salt suggests that Main Röt evaporites are present in large parts of the area. There are some indications for the presence of overpressures. Where present, these overpressures can either be viewed as an increased risk of seal breach or regarded as an opportunity. We conclude that the remaining prospectivity of the Lower Triassic in this part of the Southern Permian Basin may contain over-looked upside.