The Zechstein Stassfurt carbonate hydrocarbon system of the Thuringian Basin, Germany

The Thuringian Basin is the oldest hydrocarbon province in Eastern Germany: wet gas and oil accumulations have been discovered since 1930. After a long inactive period of about twenty years, exploration for hydrocarbons now continues with improved methods. Carbonates and evaporites of the Permian Zechstein comprise the source, reservoir and seal for the main gas and oil play in the area. Today, they are buried less than 1000 m deep over the major part of the basin. Modelling of the burial history of the basin indicates that up to 1500 m of Mesozoic strata were eroded during a Late Cretaceous inversion event. Peak hydrocarbon generation occurred just prior to this inversion, implying that hydrocarbons have been effectively trapped in the reservoirs since that time. In addition, dry gas and nitrogen appear to have been sourced from pre-Zechstein intervals, which, with respect to nitrogen, poses a severe exploration risk.