Thüringen Becken (The Thuringian Basin) is located in the central/northern part of the Thüringen state in central Germany. It is a very small and mature producing region which only has four very mature producing fields left Fahner Höhe Kirchheilingen Langensalza and Mühlhausen. All fields are operated by GDF Suez. No further development is expected on these fields. We have modelled the Thüringer Becken region as a whole from 1991 onwards using individual field production profiles but an overall opex per barrel methodology.