Petroleum assessment of the Mesozoic succession in the Höllviken Graben and on the Skurup Platform, southern Sweden

Abstract

Investigations of the subsurface Mesozoic succession of SW Skåne, southern Sweden, have from the 1940s and onwards yielded a substantial amount of data and drill cores, but no hydrocarbons. Herein, previous data are compiled and new analyses and interpretations have been added, to explain the deficiency. This is essential as speculative exploration with little geological basis tends to recur in Skåne. The subsurface of SW Skåne comprises Rhaetian to Cenomanian sandstone units with acceptable reservoir qualities, as well as potential seals. Unpublished analyses from the 1970s also indicate promising source rock conditions. Conversely, our study shows that potential Mesozoic source rocks are few, thin, low in kerogen, and primarily gas prone. Furthermore, the kerogen is thermally immature to marginally mature, due to moderate burial. Heat flux, due to Middle Jurassic tectonic and volcanic activity, is discussed as a possibility for enhanced hydrocarbon maturation in the study area, whereas external hydrocarbon influx is considered unlikely because of the structural development of the Tornquist Zone, and the pre-Mesozoic postmature state of the Palaeozoic organicrich sediments in Skåne.

Key Words:

• Petroleum
• source rock
• vitrinite reflectance
• pyrolysis
• reservoir
• sedimentary petrography
• Danish Basin
• Skåne
• Sweden