Geologisk karaktärisering av den kambriska Faluddensandstenen i Östersjön och dess lämplighet för koldioxidlagring
(2023) In Examensarbeten i geologi vid Lunds universitet GEOL02 20231Department of Geology
- Abstract
- The Geological Survey of Sweden (SGU) has spent several years investigating the Swedish bedrock to find suitable bedrock for geological storage of carbon dioxide. Deep saline aquifers are considered to have the greatest potential, and the Cambrian Faludden Sandstone subcropping in the Baltic Sea east of Gotland, shows great potential as a storage aquifer.
In this study, the drill core St. Sutarve-2018 from southern Gotland has been studied to investigate the mineralogy and texture of the Faludden Sandstone, with the aim of more accurately investigating its suitability for carbon dioxide storage. Three thin sections from different depths (547.3 m, 552.4 m and 559.35 m) from St. Sutarve-2018 were studied under a polarizing microscope. Two... (More) - The Geological Survey of Sweden (SGU) has spent several years investigating the Swedish bedrock to find suitable bedrock for geological storage of carbon dioxide. Deep saline aquifers are considered to have the greatest potential, and the Cambrian Faludden Sandstone subcropping in the Baltic Sea east of Gotland, shows great potential as a storage aquifer.
In this study, the drill core St. Sutarve-2018 from southern Gotland has been studied to investigate the mineralogy and texture of the Faludden Sandstone, with the aim of more accurately investigating its suitability for carbon dioxide storage. Three thin sections from different depths (547.3 m, 552.4 m and 559.35 m) from St. Sutarve-2018 were studied under a polarizing microscope. Two additionally thin sections from drill cores B7 (862 m) and B9 (1030 m), which are drilled in the Baltic Sea, were also used in the study to determine whether there are differences in the sandstone depending on burial depth. By point counting (modal analysis), the mineralogical composition of the sandstone was investigated. Additionally, an ocular description of the Faludden Sandsten in St. Sutarve-2018 was made, resulting in a log. The results show that the sandstone mainly consists of white to light grey, fine-grained and well-sorted quartz sand. Thin horizontal layers of clay, as well as precipitates of pyrite are common. Vertical fissures are also observed. In addition to quartz, the accessory minerals consist mainly of pyrite and weathered feldspar. Pressure dissolution and compaction become more noticeable at greater depths, while porosity decreases. Siliceous cement is most common, often as quartz overgrowths, but carbonate cement is also observed. The modal analyses in this study are comparable to previously performed analyses and give largely the same results. The porosity of the sandstone varies slightly between different studies, but overall, it corresponds well with the requirements for carbon dioxide storage. The permeability, thickness and extent of the sandstone also indicate that it is suitable for carbon dioxide storage. Further investigations should focus on mapping heterogeneities in the bedrock, such as fractures, impermeable layers and variations in porosity and permeability, as these can have a major impact on carbon dioxide diffusion paths. (Less) - Abstract (Swedish)
- Sveriges geologiska undersökning (SGU) har ägnat flera år åt att undersöka den svenska berggrunden för att utreda möjligheterna för geologisk lagring av koldioxid. Djupt liggande akviferer anses ha störst potential och den kambriska Faluddensandstenen, som finns i Östersjön öster om Gotland, visar stor potential som lagringsakvifer. I denna studie har borrkärnan St. Sutarve-2018 från södra Gotland studerats för att undersöka sandstenens mineralogi och textur, i syfte att noggrannare utreda dess lämplighet som lagringsakvifer för koldioxid. Tre tunnslip från olika djup (547,3 m, 552,4 m och 559,35 m) från St. Sutarve-2018 studerades under polarisationsmikroskop. Två kompletterande tunnslip från borrkärnorna B7 (826 m) och B9 (1030 m) som är... (More)
- Sveriges geologiska undersökning (SGU) har ägnat flera år åt att undersöka den svenska berggrunden för att utreda möjligheterna för geologisk lagring av koldioxid. Djupt liggande akviferer anses ha störst potential och den kambriska Faluddensandstenen, som finns i Östersjön öster om Gotland, visar stor potential som lagringsakvifer. I denna studie har borrkärnan St. Sutarve-2018 från södra Gotland studerats för att undersöka sandstenens mineralogi och textur, i syfte att noggrannare utreda dess lämplighet som lagringsakvifer för koldioxid. Tre tunnslip från olika djup (547,3 m, 552,4 m och 559,35 m) från St. Sutarve-2018 studerades under polarisationsmikroskop. Två kompletterande tunnslip från borrkärnorna B7 (826 m) och B9 (1030 m) som är borrade i Östersjön användes också i studien för att studera om det förekommer skillnader i sandstenen beroende på begravningsdjup. Genom punkträkning (modalanalys) undersöktes sandstenens mineralogiska sammansättning. Dessutom gjordes en okulär beskrivning av Faluddensandstenen i St. Sutarve-2018, vilken resulterade i en logg. Resultaten visar att sandstenen främst består av vit till ljusgrå, finkornig och välsorterad kvartssand. Tunna horisontella lager av lera, samt utfällningar av pyrit är vanligt förekommande. Även vertikala sprickor observeras. Utöver kvarts består de accessoriska mineralen främst av pyrit och vittrade fältspater. Tryckupplösning och kompaktion blir mer påtagligt vid successivt större djup, samtidigt som porositeten minskar. Kiselcement dominerar bland sekundära mineraliseringar, ofta som kvartsöverväxter, men karbonatcement förekommer också. Resultatet av modalanalyserna i denna studie är jämförbara med tidigare utförda analyser och ger i stort sett samma resultat. Porositeten i sandstenen varierar något mellan olika studier, men övergripande överensstämmer den väl med kraven för koldioxidlagring. Även permeabiliteten, formationens tjocklek och utbredning tyder på att sandstenen är lämplig för koldioxidlagring. Vidare undersökningar bör fokusera på att kartlägga heterogeniteter i berggrunden, såsom sprickor, impermeabla lager och variationer i porositet och permeabilitet då dessa kan ha stor inverkan i koldioxidens spridningsvägar. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9133399
- author
- Bengtsson, Kaisa LU
- supervisor
-
- Mikael Calner LU
- Mikael Erlström LU
- Peter Dahlqvist LU
- organization
- course
- GEOL02 20231
- year
- 2023
- type
- M2 - Bachelor Degree
- subject
- keywords
- Koldioxidlagring, djupt liggande akvifer, Faludden, St. Sutarve-2018, CO2-storage, deep saline aquifers
- publication/series
- Examensarbeten i geologi vid Lunds universitet
- report number
- 664
- language
- Swedish
- id
- 9133399
- date added to LUP
- 2023-08-04 11:48:43
- date last changed
- 2023-08-04 11:48:43
@misc{9133399,
abstract = {{The Geological Survey of Sweden (SGU) has spent several years investigating the Swedish bedrock to find suitable bedrock for geological storage of carbon dioxide. Deep saline aquifers are considered to have the greatest potential, and the Cambrian Faludden Sandstone subcropping in the Baltic Sea east of Gotland, shows great potential as a storage aquifer.
In this study, the drill core St. Sutarve-2018 from southern Gotland has been studied to investigate the mineralogy and texture of the Faludden Sandstone, with the aim of more accurately investigating its suitability for carbon dioxide storage. Three thin sections from different depths (547.3 m, 552.4 m and 559.35 m) from St. Sutarve-2018 were studied under a polarizing microscope. Two additionally thin sections from drill cores B7 (862 m) and B9 (1030 m), which are drilled in the Baltic Sea, were also used in the study to determine whether there are differences in the sandstone depending on burial depth. By point counting (modal analysis), the mineralogical composition of the sandstone was investigated. Additionally, an ocular description of the Faludden Sandsten in St. Sutarve-2018 was made, resulting in a log. The results show that the sandstone mainly consists of white to light grey, fine-grained and well-sorted quartz sand. Thin horizontal layers of clay, as well as precipitates of pyrite are common. Vertical fissures are also observed. In addition to quartz, the accessory minerals consist mainly of pyrite and weathered feldspar. Pressure dissolution and compaction become more noticeable at greater depths, while porosity decreases. Siliceous cement is most common, often as quartz overgrowths, but carbonate cement is also observed. The modal analyses in this study are comparable to previously performed analyses and give largely the same results. The porosity of the sandstone varies slightly between different studies, but overall, it corresponds well with the requirements for carbon dioxide storage. The permeability, thickness and extent of the sandstone also indicate that it is suitable for carbon dioxide storage. Further investigations should focus on mapping heterogeneities in the bedrock, such as fractures, impermeable layers and variations in porosity and permeability, as these can have a major impact on carbon dioxide diffusion paths.}},
author = {{Bengtsson, Kaisa}},
language = {{swe}},
note = {{Student Paper}},
series = {{Examensarbeten i geologi vid Lunds universitet}},
title = {{Geologisk karaktärisering av den kambriska Faluddensandstenen i Östersjön och dess lämplighet för koldioxidlagring}},
year = {{2023}},
}