Porosity and Permeability Depth Trends, Examples from the Danish Upper Triassic−Upper Jurassic Gassum Formation

ty-depth and permeability-depth trends, established for all cored intervals of the Gassum Formation. The porosity-depth and permeability-depth trends represent sandstones alteration during burial due to mechanical compaction and diagenesis. The focus of this study is on the Gassum Formation, which has the largest potential and is the main target for planned geothermal wells in Denmark, as it is widely distributed and generally occurs within the depth interval of 800-3000 m, thereby reaching sufficient high temperatures and still assumed to maintain the required porosity and permeability. The Gassum Formation occurs with thicknesses of 50–150 m in central and distal areas of the Danish part of the Norwegian−Danish Basin, thickening locally in association with salt structures and major faults (up to 300 m in the Sorgenfrei−Tornquist Zone) and thinning or being absent on the structural highs, such as the Skagerrak−Kattegat Platform and the Ringkøbing−Fyn High (Fig. 1). The Gassum Formation consists of shoreface, fluvial, estuarine, lacustrine, lagoonal and marine facies (Nielsen 2003).