Integrated evaluation of deep autochthonous play in Northern Calcareous Alps, Austria

The Grünau-West lead is a subthrust, fault block play in the extensional autochthonous section of the Northern Calcareous Alps. The prospect is located in the province of Upper Austria, about 200 km west of Vienna. This region lies at the leading edge of the Northern Calcareous Alpine thrust sheets. The Calcareous Alps and Flysch were thrust over Late Eocone to Oligocene Molasse sediments and a Mesozoic autochthonous section overlying crystalline basement. Hydrocarbon production has been established in the foreland Molasse Basin (operated by Rohöl-Aufsuchungs GmbH), 20 km north of Grunau- West. In the foreland Molasse Basin, north-south and east-west striking normal faults form structural traps that produce oil and gas from autochthonous Eocene and Mesozoic reservoirs. The largest foreland field is Voitsdorf. Both fields produce from Jurassic carbonates, Cretaceous and Eocene sands. The source and seal are lower Oligocene shales which are immature in the foreland; the main source kitchen area is to the south of Grünau.