New Depositional Architecture for an Old Giant: The Matzen Field, Austria
Reinhard Fuchs, Walter Hamilton, 2006. "New Depositional Architecture for an Old Giant: The Matzen Field, Austria", The Carpathians and Their Foreland: Geology and Hydrocarbon Resources, Jan Golonka, Frank J. Picha
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Geophysical, sequence-stratigraphic, and petrophysical evaluation of the main oil and gas reservoirs of the Matzen field in the central Vienna basin resulted in a revised field architecture, and provided new insights into middle Miocene (Badenian, Sarmatian) depositional settings. The latest analysis suggests that the reevaluation of this mature field not only allows a better explanation of production history, but has also led to further successful redevelopment activities.
The structural setting of the Vienna basin is the result of subsidence, extension, and a final phase of subsidence. Compressional, transgressional, and extensional events had a strong influence on the basin configuration and sediment distribution. The Matzen field illustrates these pull-apart and piggyback mechanisms clearly. It is an elongated anticline (Matzen anticline), bounded by a pull-apart graben in the north (Matzen fault system), a fault complex in the west (Bockfliess fault system), and another fault zone in the south (Markgraneusiedl fault zone).
Three depositional cycles (Matzen cycles) have been subdivided into some 30 sequences.
The first Matzen cycle culminates with the transgressive Matzen sand, the main producing horizon in the field.
Produced during the Matzen main cycle (second Matzen cycle), marine prograding delta systems of Badenian age contain the main oil reservoirs. The 9th Tortonian horizon is a textbook example of a shelf-slope basin sucession. Within six sublayers, the shelf edge advances some 2 km (1.2 mi) from north to south. Transgressive meandering channel systems of Sarmatian age hold the main gas reservoirs that are partly used as gas storage. The 5th Sarmatian horizon was deposited in a shallow-marine deltaic setting. During a sea level drop, the depocenter shifted southward with simultaneous incision of a widespread channel system into the underlying 6th Sarmatian horizon. The base of the system represents an important sequence boundary. Final isolation of the Vienna basin created brackish conditions.
The third Matzen cycle developed as a thick series of lacustrine prograding delta sequences of the Pannonian (upper Miocene).