Differentiation of Palaeogene sand by glauconitic and geochemical fingerprinting, Siri Canyon, Danish North Sea

Mette Olivarius,Christian Knudsen,Johan B Svendsen

doi:10.34194/geusb.v23.4802

Mette Olivarius, Christian Knudsen + Show 1 more

Open Access

https://doi.org/10.34194/geusb.v23.4802

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Abstract

The submarine Siri Canyon is NE–SW-oriented and located in the Danish North Sea (Fig. 1). It contains a number of oil reservoirs with glauconite-rich sand. The reservoirs of interest in the Nini oil field are the Late Paleocene Tyr Member of the Lista Formation and the Kolga Member of the Sele Formation (Schiøler et al. 2007), presumably of Early Eocene age. These members have previously been known as the Ty and Hermod members (Hamberg et al. 2005; Poulsen et al. 2007). The sand shows signs of injection, both in cores and in seismic data. The aim of this work is to chemically characterise and fingerprint the sand in order to reveal the origin of the sand found in three horizontal wells, which could have been injected from one or both of the Tyr and Kolga members. Core samples were collected from two vertical wells of known stratigraphy to make a basis of comparison, whereas samples of the cuttings were collected from the three horizontal wells with ages primarily corresponding to the Kolga Member. The purpose was moreover to evaluate whether cuttings samples can be used for fingerprinting as an alternative to core samples.

Highlights

The submarine Siri Canyon is NE–SW-oriented and located in the Danish North Sea (Fig. 1)
Most of the sand is fairly loose, but parts of the Tyr Member are cemented by quartz and calcite as it was located below the oil-water contact, whereas cementation was largely inhibited by oil in most of the Kolga Member
The advantages of this method compared with X-ray fluorescence (XRF) are that the former measures a wider range of trace elements including rare-earth elements (REE), and that the detection limits are lower than those of XRF, which allows more accurate interpretation of elements found in low concentrations

Summary

Introduction

The submarine Siri Canyon is NE–SW-oriented and located in the Danish North Sea (Fig. 1) It contains a number of oil reservoirs with glauconite-rich sand. The reservoirs of interest in the Nini oil field are the Late Paleocene Tyr Member of the Lista Formation and the Kolga Member of the Sele Formation (Schiøler et al 2007), presumably of Early Eocene age. These members have previously been known as the Ty and Hermod members (Hamberg et al 2005; Poulsen et al 2007). Most of the sand is fairly loose, but parts of the Tyr Member are cemented by quartz and calcite as it was located below the oil-water contact, whereas cementation was largely inhibited by oil in most of the Kolga Member

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Conclusion