| Summary: | Increased anthropogenic emission of carbon dioxide (CO2) into the Earth’s atmosphere since the industrial revolution has enhanced the greenhouse effect and contributed to global climate change. Controlling atmospheric CO2 emissions is thus essential to mitigate the environmental and socio-economic consequences related to these changes. Carbon capture and storage (CCS) was proposed as one possible option to control anthropogenic CO2 emissions, and is particularly viable at CO2 point sources such as coal-fuelled power plants. CCS was tested and applied globally in a variety of geological and top-side settings within the past decade, with varying success. In Longyearbyen, the main settlement on the Norwegian high-Arctic Svalbard archipelago, CO2 may be captured at the local coal-fuelled power plant and injected into an unconventional siliciclastic target aquifer. The target aquifer, within the Late Triassic to Middle Jurassic Kapp Toscana Group, comprises an up to 300 m thick sequence of tight, naturally fractured sandstones inter-bedded with siltstones and shales. During the Early Cretaceous, igneous intrusions, collectively classified as the Diabasodden Suite, were emplaced in the target aquifer. The pilot-scale Longyearbyen CCS project envisions only modest storage volumes of CO2, with the top-side CO2 storage requirements determined by the annual CO2 emissions from the local coal-fuelled power plant (c. 60 000 tons). As part of this PhD study, the geologically complex target aquifer was characterized and represented in a static geologic reservoir model. Fieldwork (e.g. structural and stratigraphic logs, geological mapping), borehole (e.g. drill core logs and plugs, wireline logs, water injection tests, vertical-seismic-profiling survey) and regional geophysical (e.g. 2D seismic, digital elevation model, magnetic data) data sets were used as input. Two main themes relating directly to the geological heterogeneity of the target aquifer were addressed in detail: (1) the natural fracture network, and, (2) the ...
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