1887

Abstract

Summary

The present study aims at characterizing the types of fracture and the timing of phases of cementation taking place during chalk diagenesis within the Kraka Field. Three types of fractures are identified in sedimentary cores: Partially cemented, brecciated and sheared fractures. Whereas the brecciated fractures are cemented by blocky calcite cement, partially-cemented fractures can be divided into two groups. The first group shows an early, polyphase quartz cementation followed by calcite cementation. The second group contains one single phase of calcite cementation. Isotopic analysis of δ13C and δ18O were carried out using bulk rock samples and calcite cement that precipitated in intraparticle porosity and fractures. The δ13C and δ18O values range from +0.53‰ to +1.31‰ and −9.86‰ to −3.88‰, respectively. The isotopic values of calcite cement are more depleted in oxygen than bulk rock samples. In addition, calcite cement in intraparticle porosity is slightly more depleted in carbon and oxygen than in fractures, suggesting that it precipitated slightly later during burial. The resemblance in isotopic compositions in all fracture-filling cements sampled indicates similar diagenetic conditions during fracture cementation, despite a significant difference in the style of deformation recorded by the types of fractures described.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.201801485
2018-06-11
2020-04-02
Loading full text...

Full text loading...

References

  1. Abramovitz, T, Andersen, C, Jakobsen, F.C, Kristensen, L & Sheldon, E.
    [2010]. 3D seismic mapping and porosity variation of intra-chalk units in the southern Danish North Sea. In: Petroleum Geology: From Mature Basins to New Frontiers – Proceedings of the 7th Petroleum Geology Conference. pp. 537–548
    [Google Scholar]
  2. Astratti, D., Aarre, V., Vejbæk, O. V. and White, G
    [2015] Mapping and time-lapse analysis of South Arne Chalk fault network using new developments in seismic dip computation. Geological Society, London, Special Publications406, 331–358.
    [Google Scholar]
  3. Bisdom, K., Bertotti, G, & Nick, H. M.
    [2016]. The impact of in-situ stress and outcrop-based fracture geometry on hydraulic aperture and upscaled permeability in fractured reservoirs. Tectonophysics, 690, 63–75.
    [Google Scholar]
  4. Egeberg, P. K. and Saigal, G. C.
    [1991] North Sea chalk diagenesis: cementation of chalks and healing of fractures. Chemical Geology92, 339–354.
    [Google Scholar]
  5. Hardebol, N. J., Maier, C, Nick, H., Geiger, S., Bertotti, G, & Boro, H.
    [2015]. Multiscale fracture network characterization and impact on flow: A case study on the Latemar carbonate platform. Journal of Geophysical Research: Solid Earth, 120(12), 8197–8222.
    [Google Scholar]
  6. Hu, X., Jeans, C. and Dickinson, T.
    [2012] Geochemical and stable isotope patterns of calcite cementation in the Upper Cretaceous Chalk, UK: Direct evidence from calcite-filled vugs in brachiopods. Acta Geologica Polonica, 62, 143–172.
    [Google Scholar]
  7. Jørgensen, L.N. and Andersen, P.M.
    [1991] Integrated study of the Kraka Field. Society of Petroleum Engineers23082.
    [Google Scholar]
  8. Moreau, J., Boussaha, M., Nielsen, L., Thibault, N, Ullmann, C. V. and Stemmerik, L.
    [2016] Early diagenetic evolution of Chalk in eastern Denmark. The depositional record2, 154–172.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609.201801485
Loading
/content/papers/10.3997/2214-4609.201801485
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error