The Lower Palaeozoic shale gas play in Denmark

The unconventional gas resources in the Lower Palaeozoic shale of Denmark were recently assessed by the United States Geological Survey (USGS; Gautier et al. 2013). Assuming unrestricted application of best practice current technology, recoverable gas resources of 0 to 130 × 109 Nm3 gas were estimated onshore (mean = 67 × 109 Nm3 gas) and 0 to 228 × 109 Nm3 gas were estimated offshore (mean = 119 × 109 Nm3 gas), i.e. a total estimated mean of 186 × 109 Nm3 gas (Nm3: normal cubic metre, unit used for natural gas at 0°C and 101.325 kPa). Nearly all of this potential resource is assumed to be contained in the Cambro-Ordovician Alum Shale. The wide range of estimates reflects the sparse data and the geological uncertainty inherent in the still untested play. The estimated mean quantity of gas resource is comparable to the total volume of gas produced from the Danish part of the North Sea during 1972–2011 and twice the amount of the estimated remaining reserves of conventional gas in the Danish part of the North Sea.