Conceptual sketch of

The Groß Schönebeck site/plant was established during the period 1990–2006, and it includes one production well and one injection well. The figure above illustrates the position of wells and filters.

Reservoir(s): The producing reservoirs consist of sandstones and volcanic rocks: Dethlingen Silt/Sandstone (Upper Rotliegend; Elbe Subgroub), Mirow/ Parchim Sandstones (Havel Subgroub), and vulcanic rocks (dacite) of the Permo-Carboniferous. Average porosity of the sandstones: 5–18%, depending on formation.

Reservoir depth: 4100–4400 m.

Reservoir temperature: approx. 150 °C.

Problems observed: With respect to scaling, the main mineral components are native copper (Cu), magnetite (Fe3O4), laurionite (PbOHCl) and barite (BaSO4). With respect to corrosion, precipitation of copper due to galvanic corrosion is observed. Corrosion also leads the formation of Fe3O4.

Geological model for the Groß Schönebeck geothermal reservoirs: The Groß Schönebeck plant produces from three reservoirs that consist of clastic sedimentary rocks of Permian to Permo-Carboniferous age. The three producing reservoirs are located below Zechstein salt deposits, and the lithology and stratigraphy of the producing sections are:

  • Sandstones/siltstones of the Upper Rotliegend Dethlingen Formation (Elbe Subgroup)
  • Sandstones of the Upper Rotliegend Mirow/Parchim Formation (Havel Subgroup)
  • Volcanic rocks of the Permo-Carboniferous system (Lower Rotliegend).

Groß Schönebeck is located in the North German Basin, where formations from the Carboniferous to the Quaternary were deposited more or less horizontally. The reservoir sections are dominated by eolian, alluvial fan (wadi), and braided plain deposits – and high lithological heterogeneity within the different sedimentary layers is observed. Several graben structures acted as transport ways for southerly derived fluviatile sediments, with wadi-type deposits of polymictic and poorly sorted conglomerates. Aeolian sediments are mainly preserved at the southern margin of the basin and represent reworked fluviatile deposits. Mud-flat facies predominates the Mirow Formation, while braided-plain and sand-flat sediments are typical for the lower Havel Subgroup (Parchim). During the main basin subsidence (in latest Rotliegend), fluviatile sands were deposited in the southern margin of the North German Basin.

Completion design, well completions and casing sizes (production well)

Well Schonebeck