Generation and origin of natural gas in Lower Palaeozoic shales from southern Sweden

Authors

  • Niels Hemmingsen Schovsbo Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, DK-1350 Copenhagen K, Denmark
  • Arne Thorshøj Nielsen Department of Geosciences and Natural Resource Management, University of Copenhagen. Øster Voldgade 10, DK-1350 Copenhagen K, Denmark

DOI:

https://doi.org/10.34194/geusb.v38.4395

Abstract

The Lower Palaeozoic succession in Scandinavia includes several excellent marine source rocks notably the Alum Shale, the Dicellograptus shale and the Rastrites Shale that have been targets for shale gas exploration since 2008. We here report on samples of these source rocks from cored shallow scientific wells in southern Sweden. The samples contain both free and sorbed hydrocarbon gases with concentrations significantly above the background gas level. The gases consist of a mixture of thermogenic and bacterially derived gas. The latter likely derives from both carbonate reduction and methyl fermentation processes. The presence of both thermogenic and biogenic gas in the Lower Palaeozoic shales is in agreement with results from past and present exploration activities; thermogenic gas is a target in deeply buried, gas-mature shales in southernmost Sweden, Denmark and northern Poland, whereas biogenic gas is a target in shallow, immature-marginally mature shales in south central Sweden. We here document that biogenic gas signatures are present also in gas-mature shallow buried shales in Skåne in southernmost Sweden.

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Published

2017-07-31

How to Cite

Hemmingsen Schovsbo, N. ., & Thorshøj Nielsen, A. . (2017). Generation and origin of natural gas in Lower Palaeozoic shales from southern Sweden. GEUS Bulletin, 38, 37–40. https://doi.org/10.34194/geusb.v38.4395

Issue

Section

RESEARCH ARTICLE | SHORT

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