The importance of fault damage zones for fluid flow in low-permeable carbonate rocks – Fault-related compaction fronts in the Danish North Sea

F.W.H. Smit, L. Stemmerik, M.E. Smith, P.T. Staudigel, M. Lüthje, M. Welch, Frans van Buchem, P.K. Swart

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4 Scopus citations


This study documents the timing and driving forces of the formation of fault-related compaction fronts in the Upper Cretaceous to lowermost Paleogene Chalk Group in the southern Danish Central Graben, based on the integration of 3D seismic, petrophysical log and clumped isotope data. The compaction fronts reflect zones in the low permeable Chalk Group that underwent time-transgressive fault reactivation and pore fluid venting driven by movements of deeper salt and inversion movements. The fault-damage zones formed narrow permeability fairways that facilitated better drainage of compaction-driven pore fluids trapped in the matrix, eventually resulting in preferential mechanical compaction of the chalk. Salt doming during the Paleocene – Early Eocene, possibly linked to regional inversion tectonics, led to an initial phase of fault reactivation, offsetting the entire Chalk Group; pockmarks within this interval indicate release of pressurized fluids on the seafloor. Clumped isotope data from calcite-cemented veins associated with these fault-damage zones indicate precipitation from fluids that likely originated from Lower to Middle Jurassic strata at the root of these faults some 1500 m below the Chalk Group. Local thickening of the Paleocene to Lower Miocene Rogaland and Hordaland Groups matches a 20–50 m thinning of the chalk within the compaction fronts. This indicates that preferential drainage and compaction continued as the chalk became buried with clays, which became affected by polygonal-faulting causing episodic leak-offs. The results indicate that fault damage zones in low-permeability rocks may initially act as permeability fairways, but the improved drainage of formation fluids may over time cause preferential mechanical compaction and calcite precipitation. At present, the fault-related compaction fronts form low-porosity chalk bodies that may have acted as seals and/or re-directed fluid migration. The results have important implications for static and dynamic reservoir models, also in the light of Carbon Capture Storage and geothermal energy extraction and storage.
Original languageEnglish (US)
Pages (from-to)105993
JournalMarine and Petroleum Geology
StatePublished - Nov 1 2022

Bibliographical note

KAUST Repository Item: Exported on 2022-12-09
Acknowledgements: This work was supported by the Danish Offshore Technology Centre (DTU Offshore) under the Advanced Water Flooding program. The clumped isotope facility at the University of Miami has been supported by NSF awards EAR-0926503, OCE-1537727, and OCE-1635874 to PKS. This study forms a follow-up to the first authors PhD project (Smit et al., 2018) at the Danish Offshore Technology Centre (DTU Offshore). The Danish Underground Consortium (Total, Noreco, and Nordsøfonden) is kindly acknowledged for providing seismic and well data and the permission to publish the results. Colleagues at the Stable Isotope Laboratory at University of Miami (Gregor Eberli, Greta Mackenzie, and Amel Saied) are kindly thanked for hosting the clumped isotope project as part of the Research Stay Abroad. We would like to thank Schlumberger for providing academic licenses for Petrel E&P. The authors have no conflicts of interest to declare.

ASJC Scopus subject areas

  • Economic Geology
  • Oceanography
  • Stratigraphy
  • Geophysics
  • Geology


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