More knowledge about the oil and gas potential in the North Sea
Although the Central Graben in the North Sea is a mature oil province, knowledge about the hydrocarbon potential of its Cretaceous strata is inadequate. GEUS is working to procure this knowledge under the CRETSYS project (The Cretaceous Petroleum System in the Danish Central Graben). The CRETSYS project emerged from the PETSYS project and is funded by oil companies active in oil and gas exploration in Denmark. Work includes new interpretations and comparison of 3D seismic and stratigraphic data from wells, and it will result in a coherent framework for the complex geological Cretaceous strata and a description of basin development. Furthermore, the geologists on the project are working on a list of reservoir properties, e.g. porosity and permeability, and they are preparing an outline of the regional variation in oil migration routes from the Jurassic source rocks into the chalk beds. During 2015, two workshops were held at which the results were presented, and a GIS-based website is under development from which companies can retrieve data and survey results.
Preparation of oil and gas licensing rounds in Greenland
The Government of Greenland has announced two licensing rounds for oil and gas exploration, one in 2016 for onshore areas on Disko and Nuussuaq in West Greenland and one in 2017 for offshore areas in Baffin Bay offshore North-West Greenland. Occasioned by the Greenland Ministry of Mineral Resources, GEUS updated a GIS compilation with petroleum geology from scientific surveys and exploration in the Disko-Nuussuaq area. The compilation includes sedimentological and stratigraphical data from the onshore areas and seismic data from the Vaigat strait between Disko and Nuussuaq. Furthermore, in 2015 GEUS completed an extensive survey for the Ministry of Mineral Resources of the geological properties of an area of around 200,000 km 2 in the easternmost part of Baffin Bay. This area has been subject to oil exploration activities following licensing rounds in 2007-2008 and 2010, and extensive geophysical and geological data have been collected. GEUS updated the existing survey with new data so that there is now an improved and up-to-date basis for appraising the geological development and hydrocarbon potential of the area.
Compilation of knowledge on shale gas
In August, Total E&P Denmark completed the first shale gas test well at Dybvad in Nordjylland following three months of drilling. Total and the state-owned oil and gas company Nordsøfonden have discovered gas in the alum shale in the Danish subsurface. However, the shale layer examined turned out to be considerably thinner than expected and, therefore, gas production from the shale is not feasible. While the surveys in Denmark were ongoing, GEUS also continued work on surveying shale gas at European level.
The estimation of shale-gas resources in Europe is still very uncertain, e.g. due to limited exploration and lack of actual production experience. Working with the Joint Research Centre (JRC) of the European Commission, EuroGeoSurveys (EGS) has launched the EUOGA project, which is currently compiling existing knowledge about the European shale-gas potential from EU and ESG member states. The project is managed by GEUS. In our own backyard, GEUS contributed to a scientific study commissioned by the Ministry of Environment and Food which aimed at putting existing international knowledge about the extraction of shale gas into a Danish context. This work was headed by the Technical University of Denmark and also counted contributors from the Danish Centre for Environment and Energy at Aarhus University.
Deep and shallow geothermal energy
Climate change calls for new energy solutions which can reduce emissions of CO2
into the atmosphere. The Danish government is aiming for a fossil-fuel-free Denmark by 2050. The Danish subsurface contains a large green energy resource of geothermal heat in reservoirs at around 1-3 km depth, as well as a resource of shallow geothermal energy which involves exploiting the temperatures in the top 100-200 m in geothermal boreholes. Furthermore, there are possibilities to exploit the heat or to store it seasonally in geological strata at depths of 0.2-1 km.
In 2015, GEUS completed a seismic survey of a series of key geological horizons with geothermal potential. This means there is now a survey basis for the required detailed appraisals of the depth conditions, quality, thickness and size of the reservoirs. Furthermore, GEUS finalised the first version of a GIS web application for the Danish Energy Agency with knowledge and data on geothermal energy. The web application contains a number of 3D depth maps of the geothermal reservoirs as well as thematic maps showing geological key parameters and parameters of significance for geothermal production properties. Finally, the application contains a geological screening of the subsoil beneath 28 areas, mainly urban areas, selected in consultation with the Danish Energy Agency.
In the area of shallow geothermal energy, there has been demand from the industry to expand a web tool developed by GEUS for planning new geothermal boreholes with data on geology and thermal properties of soil. In 2015, this tool was further developed to include an interface to an energy calculation program developed by the Danish Technological Institute, so that geological information can be included directly when planning new geothermal boreholes. GEUS also finalised its contribution to the EU REGEOCITIES project on identification and removal of administrative barriers to establish geothermal installations. In this connection, in collaboration with ENVINA, GEUS held a course for municipal employees and published a guide on how to
establish closed-loop geothermal boreholes