Integrated Frontier Exploration: Structural Atlas of the NE Rockall Basin
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Astute Geoscience and ARK CLS have teamed up to produce a new integrated interpretation of 2D broadband seismic, well, gravity and magnetic data covering the NE Rockall Basin, West Flannan Basin, West Lewis Basin and Wyville-Thomson Ridge. The “Structural Atlas of the NE Rockall Basin” is designed to assist companies considering applying for acreage in the region or teams looking for a concise and robust overview of the geology and potential of the area.
The NE Rockall region lies along-strike from major oil and gas discoveries in the West of Shetlands and major gas discoveries in the Irish Sector. Furthermore, the Benbecula gas discovery indicates the presence of a functioning hydrocarbon system in the NE Rockall Basin. However, the region is geologically complex and, historically, exploration has been hindered by the issues associated with seismic imaging beneath the shallow Paleogene basaltic facies, which blanket much of the region.
In 2016, the UK Oil and Gas Authority (OGA) released 10,013 km of newly acquired 2D long offset broadband seismic data, 4,400 km of legacy data and 1,050 km of reprocessed Western Geco multi-client legacy data covering the eastern and northern parts of the Rockall Trough. Additional co-located marine gravity and magnetic data, and data from 12 wells were also released.
The 2D broadband seismic data released by the OGA represents a significant improvement in imaging of the structure of the region, but it is still affected by the difficulties of imaging beneath shallow basaltic facies. Gravity and magnetic data are not inhibited by the acoustic impedance contrast that challenges seismic data, so can be used to great effect on volcanic passive margins. However, gravity and magnetic data suffer from the non-uniqueness issue, which means multiple configurations of subsurface density and susceptibility can produce the same anomalies. By combining constraints from the seismic, well, gravity and magnetic data released by the OGA, the ambiguities in interpretation of each individual data-type and the number of possible Earth models are reduced, whilst fresh insights into the geological evolution of the region are achieved.
The integrated interpretation we present indicates the likely presence of an inverted pre-Cretaceous depocentre within the Wyville-Thomson Ridge, and better delineates structures, basins, highs and igneous features throughout the region.
The Astute Geoscience/ARK CLS Structural Atlas of the NE Rockall Basin comprises:
A fully tied network of 20 2D/2.5D density and velocity models (in time and depth)
Key 3D horizons derived from seismic and potential field modelling
A sediment thickness map derived from seismic and potential field interpretations
GIS-based map of structural elements shown on key potential field grids
A detailed report containing:
A comprehensive review of the literature.
Synthesis of geological and exploration information.
Detailed descriptions of advanced data processing and interpretation methods.
Detailed results and descriptions of the geological models.
Discussion of the geological evolution and exploration potential of the region.