Text by Kristine Larssen.
In mid-late August, master student Kristine Larssen (UiT/UNIS) and her two field assistants, Niklas Schaaf (UiO/UNIS) and arctic nature guide Hilde Marita Haraldsvik, were conducting fieldwork in parts of southern Dickson Land on Svalbard. The two-week long fieldwork was a part of Kristine´s master thesis which focus on a structural characterization of the carbonates of the Late Permian Kapp Starostin Formation.
A fixed tent camp with trip wires was established on an elevated hill in the mouth of Esperantodalen, a narrow valley with steep mountains sides. For extra polar bear protection, the field group was accompanied by Bamse, a very cuddly and observant husky. No polar bear was spotted during the two-week long campaign, but Bamse was good to inform about reindeers and polar foxes lurking in the area.
The first days of the field campaign were used to get an overview of the accessible outcrops in the area. The outcrops in the valleys are superbly exposed, but steepness made it challenging to reach them. Several outcrops in the different valleys around Kapp Wijk were investigated to obtain data from outcrops with different orientations. Outcrops in Esperantodalen and Idodalen were used to gather structural data.
In a reservoir, faults and fractures represent abrupt changes in the reservoir properties, and influence both permeability and porosity. They give a significant challenge in reservoir characterization and affect the fluid flow behaviour within a reservoir.
The objective and aim of Kristine´s master thesis is to use the collected structural field data to construct a discrete fracture network model – which will be used to get a better understanding of the reservoir quality and fluid flow pathways within the Kapp Starostin Formation, as an analogue to carbonate reservoirs elsewhere. The study will contribute to an improved characterization of fracture systems for subsurface fractured carbonate reservoirs, which is important to understand fluid flow.
The Kapp Starostin consists of cold-water spiculitic cherts with sub-ordinate limestones, shales and glauconitic sandstones (Ezaki, et al., 1994; Blomeier, et al., 2013). The Gotha discovery by Lundin in 2013 was made in cool-water carbonates in the Røye Formation, which is the equivalent in the Barents Sea for the Kapp Starostin Formation in Svalbard. Carbonate and spiculitic chert reservoirs commonly have a high porosity and permeability due to secondary dissolution porosity, fracturing and karstification processes. This type of reservoirs represents a new and important play type in some parts of the Arctic, and in the Barents Sea in particular.
Kristine´s dataset for the thesis will mainly consists of structural measurements collected during the fieldwork, in addition to structural data from 3D virtual outcrop models. During fieldwork, several hundred high-resolution digital photos were taken for photogrammetry. The digital photos will be used to construct 3D virtual outcrops in Agisoft Photoscan that will be analyzed for additional structural measurements from remote and inaccessible outcrops.
References:
Blomeier, D., Dustira, A. M., Forke, H. & Scheibner, C., 2013. Facies analysis and depositional environments of a storm-dominated, temperate to cold, mixed siliceous-carbonate ramp: The Permian Kapp Starostin Formation in NE Svalbard. Norsk Geologisk Tidsskrift, Issue 2, pp. 75-93.
Ezaki, Y., Kawamura, T. & Nakamura, K., 1994. Kapp Starostin Formation in Spitsbergen: A sedimantary and faunal record of Late Permian paleoenvironments in an Arctic region. Canadian Society of Petroleum Geologist, pp. 647-655.
