There is a lot of focus on developing new technologies to assist in the exploration and development of hydrocarbon fields at present. These new technologies are innovative and many are successful in improving the chances of discovery and recovery from new and older oil and gas fields.
However, sometimes it is important to explore past studies and established techniques to uncover a new understanding. Exploration, field development, and correlation in the northern North Sea and Norwegian Sea should not ignore the value that can be obtained from a heavy mineral provenance study.
Heavy minerals constitute the high-density component of sediments and can be diagnostic of their source area, making them invaluable for provenance studies. Heavy mineral analysis and associated techniques have been completed in multiple areas across the North Sea and Norwegian Sea basins.
They have uncovered a detailed understanding of the provenance of reservoir sandstones in multiple basins depositing from the Devonian through to the Eocene. Detailed studies have pinpointed where and when sediment transport systems have switched from derivation to the east, coming from varying regions of the Norwegian landmass, or the west, and the Greenland margin, see Figure 1.
This has provided a greater understanding of sediment transport at the time of deposition in Vøring and Møre basins and across the Trondelag Platform (Morton et al, 2005; Szulc et al, 2022) and the Heidrun Field of the Halten Terrace (Morton et al, 2009; Morton and Chenery, 2009).
The understanding from these studies provides a wider understanding of provenance that can be utilised to better understand the adjacent areas. The studies have produced a framework for understanding the heavy mineral signatures of the various source regions from the Greenland margin (provenance signature MN2i – upper-amphibolite facies rocks of East Greenland and MN4 – granulite facies rocks of East Greenland; Morton et al, 2005., Morton and Chenery, 2009) to regions of the Norwegian margin (MN1 – northern mid-Norway, MN3 – western Norway and MN5 – mid-Norway; Morton et al, 2005, Morton et al, 2009).
In addition to adding a wider understanding of provenance to the northern North and Norwegian Seas, heavy mineral analysis has also provided a proven tool for correlation with this wide area of exploration and production. All examples given here can be found in Morton and McGill (2018).
Conventional heavy mineral studies alone can be used to correlate reservoir sandstone in the Strathmore and Clair Fields, West of Shetland. The Clair Field correlation is so detailed that the technique can be used at well site to assist in geo-steering decisions (Morton and Milne, 2012).
In the Central and Northern North Sea, associated techniques can be utilised for correlation. Grain morphology can be used as a correlation tool in the Central North Sea in the Culzean field. In the Northern North Sea, garnet geochemistry techniques can be used to assist correlation of the Oseberg field, and rutile and zircon techniques can help to correlate the Magnus Field.
To summarise, heavy mineral analysis is an established technique in adding value and understanding to exploration studies across the North and Norwegian Sea basins. This proven framework should be used to its full potential moving forward.
During the NCS Exploration – Recent Advances in Exploration Technology conference in Oslo in August, HM Research presented a multi-faceted approach to analysing heavy minerals for exploration.
DR PAULA MCGILL
HM Research Norway AS
References
Morton, A. C., and Chenery, S. R. 2009. Detrital Rutile Geochemistry and Thermometry as Guides to Provenance of Jurassic-Paleocene Sandstones of the Norwegian Sea. Journal of Sedimentary Research 79(7) 540-553
Morton, A. C., and McGill, P. J. 2018. Correlation of Hydrocarbon Reservoir Sandstones Using Heavy Mineral Provenance Signatures: Examples from the North Sea and Adjacent Areas. Minerals, 8, 564.
Morton, A. C., and Milne, A. 2012. Heavy mineral stratigraphic analysis on the Clair Field, UK, west of Shetlands: a unique real-time solution for red-bed correlation while drilling. Petroleum Geoscience, 16, 115-128.
Morton, A. C., Hallsworth, C., Strogen, D., Whitham, A. and Fanning, M. 2009. Evolution of provenance in the NE Atlantic rift: The Early-Middle Jurassic succession in the Heidrun Field, Halten Terrace, offshore Mid-Norway. Marine and Petroleum Geology 26 1100-1117
Morton, A.C., Whitham, A. G., and Fanning, C. M. 2005. Provenance of Late Cretaceous to Paleocene submarine fan sandstones in the Norwegian Sea: Integration of heavy mineral, mineral chemical and zircon age data. Sedimentary Geology 182 3-28
Szulc, A. G., Morton, A. C., Whitham, A. G., Hemming., S. R. and Thomson, S. N. 2022. Establishing a Provenance Framework for Sandstones in the Greenland-Norway Rift from the Composition of Moraine/Outwash Sediments. Geosciences, 12, 73.