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Caprock Characterization of the Northern Lights CO2 Storage Project, Offshore Norway
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, EAGE GeoTech 2022 Sixth EAGE Workshop on CO2 Geological Storage, Apr 2022, Volume 2022, p.1 - 5
Abstract
Summary
This study investigates the caprock quality of Early Jurassic Drake Formation shales drilled in 17 wells in four oil and gas exploration blocks in the Aurora CO2 storage site, the northern North Sea using the Young’s modulus-Poisson’s ratio rock physics template. The template computes theoretical values of dynamic elastic properties of common constituents (e.g., clay, quartz, calcite, and organic matter) and helps characterize caprock behaviors (brittle versus ductile). Results show that the Drake Formation shales in the Aurora area have a wide range of Young’s modulus and Poisson’s ratio values and behave predominantly ductile to less ductile. Brittleness is a complex function of rock strength, lithology, texture, and control caprock shear failure and fracture potential. The brittleness behavior of Drake Formation shales deviates significantly compared to the classification proposed by Perez and Marfurt (2014) . Also, two other elastic property-based brittleness indices suggested by Fawad and Mondol (2021) and Grieser and Bray (2007) differ. The studied wells have a wide range of structural depth, explaining the diagenetic variation, hence variable brittleness indices. The discrepancies among the brittleness indices warrant the need for basin-specific or even formation-specific templates if the formation differences are significant.
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