詳細な石油システム解析から見えるノルウェー堆積盆地の石油ポテンシャル

抄録

Norway is one of the major oil and gas producing countries in Europe. Main production is done from the North Sea in lower latitude with the contribution from the Norwegian Sea and Barents Sea in higher latitude, and almost same undiscovered resources is expected in these areas. Petroleum potential in Norway is guaranteed by worldclass source rocks in Upper Jurassic, and therefore the nature and the habit of the petroleum system induced by these source rocks are discussed in this paper.

In the Northern North Sea, several oil families were identified by biomarker composition, especially bisnorhopane and diasteranes. Each oil family is distributed in different areas related to specific hydrocarbon kitchens. Multidimensional basin modeling revealed that the contributions from 3 source rocks (Draupne, Heather and Brent coal) differs in each kitchen, which appears to result in above nature of oil families. The different contribution is caused by the relationship of 3 source rocks to regional carrier system in each kitchen.

The established Halten and Dønna Terrace in the Norwegian Sea appear to have similar petroleum systems as the Northern North Sea. However, in the Vøring Basin, Jurassic source rocks deeply buried, and therefore the migration of oil and gas to the Cretaceous sandstones is more complex, which is the key for future exploration in the central part of the Norwegian Sea.

In the Barents Sea, the Upper Jurassic source rock matured only in the Hammerfest Basin. Detailed biomarker analysis revealed the existence of extended tricyclic hopanes in some oils suggesting the supply from the Triassic source rock. Diamondoid analysis also suggested that marine carbonate petroleum system is working in the Barents Sea, which may be originated from the Permian source rock. The distribution of these source rocks is the key for future exploration in the Barents Sea.