Shallow geology and seabed processes, Western Barents Sea

Abstract

The project is aimed to achieve a better understanding of shallow geological\/seabed conditions and processes to support technical and environmental aspects of exploration and production along the western margin of the Hammerfest Basin and Loppa High, and in the Tromsø Basin\/lngøydjupet area. \rThe project has had the following subgoals: \r\u2022 Detectionofpockmarksandseep-related features, including water column gas flares and neo-tectonic structures\r\u2022 Investigate the occurrence of gashydrates (GH), bottom-simulating reflectors (BSR) and other related seismic anomalies\r\u2022 Establish seismostratigraphy\rThe project has the following results:\r\u2022 Bathymetry and backscatter has given an overview of Holocene surface features such as pockmarks, iceberg ploughmarks etc and their relation to subsurface geological processes. Even though numerous pockmarks were identified in two basins along the studyarea, no water colurnn gas flares were detected to indicate active gas leakage.\r\u2022 Gas and BSR-like anomalies were identified and related to gashydrate stability conditions of the study area. GHSZ modelling indicates gas hydrate stability for structure II hydrates with a few percent of ethane, propane or CO2.\r\u2022 High-resolution seismic data gave a detailed picture of depositional processes during postglacial times. Two subunits, 4W1 and 4W2, are identified within the youngest Quaternary unit 4W. They probably represent the two last glacial advances LGM I and II towards the present shelf edge.