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A summary of the methodology for the seismic stratigraphic interpretation for the 'GlaciStore' bid to IODP

Gent, C.M.A.; Stewart, M.A.; Evans, D.J.; Lamb, R.; Alcalde, J.; Heinemann, N.; Akhurst, M.C.. 2015 A summary of the methodology for the seismic stratigraphic interpretation for the 'GlaciStore' bid to IODP. Nottingham, UK, British Geological Survey, 24pp. (OR/15/072) (Unpublished)

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Abstract/Summary

This report summarises the methodology followed for the seismic interpretation of sedimentary strata that are the overburden sequence and the Palaeogene strata that are prospective CO2 storage formations, in the UK Central North Sea. The interpretation of selected 2D and 3D seismic reflection, well and borehole data in the UK North and Central North Sea is targeted to inform the preparation of the ‘GlaciStore’ proposal for scientific drilling submitted to the International Ocean Discovery Programme (IODP). Drilling sites proposed to IODP lie within the UK and Norwegian sectors of the North Sea. The methodology is described for the interpretation of seismic data for proposed sites within UK waters. The seismic interpretation was undertaken in collaboration with Norwegian members of the GlaciStore consortium. The seismic interpretation was divided into two teams according to depth, into ‘shallower and ‘deeper’ seismic interpretation activities, appropriate to the fields of expertise and experience of the interpreters. The ‘shallower seismic’ interpreters considered strata of latest Neogene and Quaternary age which were deposited during major glacial and interglacial cycles. The ‘deeper seismic’ interpreters considered slightly older strata of Mid Eocene to Quaternary in age. Seven potential UK drill sites were selected to address the scientific objectives in the proposal. 2D and 3D seismic, well, borehole and bathymetry data were used to map buried and open tunnel valleys and to identify any evidence for the presence of shallow gas in the ‘shallower seismic’ interpretation at each drill site. Only sites without any indication of shallow gas features were considered as these pose a serious hazard for drilling. 2D and 3D seismic and well datasets and existing interpretations were collated for the ‘deeper seismic’ interpretation. The hydrocarbon exploration well log data, which were found to be of variable quality, were used to identify and map a number of stratigraphical surfaces of Cenozoic age, and included Quaternary strata, around the grid of seismic lines. Maps from some of the key stratigraphical surfaces are presented, selected to inform the drilling proposal. A plot of acoustic velocity data was prepared to inform future conversion of the seismic interpretation to true vertical depth. Future work, based on the seismic interpretation undertaken to underpin the drilling proposal, is identified. Features observed within the ‘shallower’ and ‘deeper’ seismic interpretations that warrant further investigation are: a chaotic zone within the Quaternary sequence; prograding units within the Eocene Horda Formation; basin centre sandstone bodies as prospective CO2 storage strata within the Horda Formation; systematic mapping of cross-cutting, buried tunnel valleys in the Quaternary sequence from 3D seismic data.

Item Type: Publication - Report (UNSPECIFIED)
Funders/Sponsors: UK CCS Call 1 'North Sea aquifers' project
Additional Information. Not used in RCUK Gateway to Research.: This item has been internally reviewed but not externally peer-reviewed
Date made live: 04 Apr 2016 15:10 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/513372

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