| Summary: | Includes bibliographical references. 2019 Spring. Oil, and especially gas, found under the ocean floor are important natural resources of the Norwegian Sea. The objective of this study is to determine the origin and maturity of gases, correlate gases to their sources, recognize gas mixtures, and interpret post-accumulation processes in the Vøring and Møre basins. All data for the research was obtained from the open source-website of the Norwegian Petroleum Directorate (NPD) website. More than 2000 exploration wells were evaluated, and 130 gas samples were selected for this study. The molecular and isotopic composition of gas samples have been analyzed predominantly by the Institute for Energy Technology in Norway. The contents of methane to pentanes (C1-C5) and inorganic gases (CO2, N2) have been measured and the δ13C composition of methane to butanes (C1-C4) and carbon dioxide (CO2), and δ2H composition of methane, and the δ18O composition of CO2 have been determined. The vast majority of studied gases in the Vøring and Møre basins are oil-associated (mid-mature) thermogenic gases. It appears that these gases originated mostly from shale (Class B) and coal (Class D/E) organofacies within the Åre Formation (Jurassic Age), although mixing with gases from other source rock formations is also possible. Biodegraded and secondary microbial gases are also present in the study area, and these are mostly oil-dissolved gases from the Urd field. One natural gas sample extracted from a shallow gas reservoir (geohazard) in 6407/6-2 well has the primary microbial origin.
|
|---|