Chlorite meniscus cement – implications for diagenetic mineral growth after oil emplacement

Authors

  • Henrik Friis,

    Corresponding author
    1. Department of Geoscience, Aarhus University, Aarhus C, Denmark
    • Correspondence: Henrik Friis, Department of Geoscience, Høegh-Guldbergs Gade 2, Aarhus University, DK-8000 Aarhus C, Denmark. Tel.: +45 87156323;e-mail: henrik.friis@geo.au.dk

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  • Nicolaas Molenaar,

    1. Department of Geology and Mineralogy, Vilnius University, Vilnius, Lithuania
    2. Molenaar GeoConsulting, AS Utrecht, the Netherlands
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  • Thomas Varming

    1. Faroese Earth and Energy Directorate, Tórshavn, Faroe Islands
    Current affiliation:
    1. Bureau of Minerals and Petroleum, Nuuk, Greenland
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Abstract

The possible influence on diagenesis of oil migration into reservoir sandstones is important for understanding their development. Although many studies have addressed the question of continued growth of diagenetic minerals after oil emplacement, there is little clear evidence of the timing of mineral growth relative to oil emplacement, nor of the possible mechanisms of continued mineral growth. This study presents an example of continued cementation by pore-lining chlorite during and after the migration of oil into a Palaeocene turbidite sandstone reservoir near the Faroe Islands. Chlorite developed in two different textures. One texture occurs on framework grain surfaces adjacent to open pore space in contact with oil. The other texture occurs close to framework grain contacts where contact with oil appears to have been prevented by residual pore-water menisci. The meniscus crystals are larger than those from open pore, implying that diagenetic clay mineral growth has continued after oil emplacement.

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