Sequence Stratigraphy of the Badenian in the Austrian part of the Vienna Basin

Wolfgang Siedl

Research output: ThesisDoctoral Thesis

Abstract

Sequence stratigraphic investigations were performed in the Austrian sector of the Vienna Basin using new interpretation methods. 3D survey data (~1800 km²) and data from 3800 boreholes with 42.000 log curves were used as input for this study. Additional data from different disciplines were included, such as production data and core data. A new approach of 3D seismic interpretation was used to identify paleo depositional facies areas. Cross-sections through the 3D seismic cube were used to identify specific depositional facies. When distinctive seismic patterns were identified (e.g. clinoforms), these patterns were marked by contouring the major seismic reflectors on the seismic cross-section. Nearby areas were screened to confirm these patterns and picking similar facies. Distinct colour coding was used for each depositional facies. Similarly picked seismic facies (like several mapped clinoforms, orientated in different directions), where merged together to a seismic facies group. These facies groups were linked together to spatial defined depositional systems (e.g. clinoforms of a prograding delta). In a next step, genetically related systems were examined, like channel systems in the landward position of delta forests. By combining these depositional systems with mapped sequence boundaries, three Badenian 3rd order sequences were recognized and nine systems tracts were specified. The interpretation was cross-checked using well logs and core data. Focused on the Badenian succession, several gross depositional environment maps (GDE) were produced. Each of these GDE maps represents a chronostratigraphic event in one of the systems tracts. Thus, it was possible to create a continuous depositional model for the entire Badenian in the central and northern part of the Austrian sector of the Vienna Basin. Results of this thesis reveal a surprisingly high variety of Badenian depositional systems. Especially lower Badenian accommodation of the Vienna Basin was strongly related to pre-Badenian topography. The lowermost sequence (early Ba1-LST1) at the Karpatian/Badenian boundary consists of braided river systems with main sediment transport direction towards north or northeast. Two pronounced canyon systems (Mistelbach Canyon, Reinthal Canyon) on the north-western margin of the Vienna Basin connected this subaerial depositional system and the marine depositional system of the Alpine-Carpathian Foredeep in the north. The onset of early Badenian extensional faulting in the area of the Vienna Basin created subsidence and accommodation. The prevailing sub-aerial depositional system of the early Ba1-LST1 sequence changed to fully marine depositional systems of the late Ba1-LST1 sequence with a contemporaneous shift of sediment transport direction towards the east. Pre-Badenian marine sub-basins forming depocenters in early Badenian time, were backfilled till the middle Badenian. Thus, new accommodation of the middle Badenian Ba2 sequence reflects the interplay between ongoing extensional fault tectonics and major sea-level changes. Lower Badenian paleo-highs in the northern part were drowned during Ba2 sequence and two discrete middle Badenian delta systems (Mühlberg Delta, Zistersdorf Delta) of the paleo-Danube merged together. During the upper Badenian Ba3 sequence, the final drowning of the Spannberg Ridge in the centre of the basin created one major delta system (Matzen Delta) of the paleo-Danube. Taking this new approach of depositional systems prediction into account, current Badenian hydrocarbon reservoir models have to be revised. Former models predicted one uniform Badenian accommodation space for the paleo-Danube, but gross depositional environment maps based on this sequence stratigraphy model reveal significantly more complex depositional patterns. Finally, based on results of this thesis, new Badenian hydrocarbon plays were predicted and successfully dril
Translated title of the contributionSequenzstratigraphie des Badeniums im österreichischen Anteil des Wiener Beckens
Original languageEnglish
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Sachsenhofer, Reinhard, Supervisor (internal)
  • Harzhauser, Mathias, Co-Supervisor (external), External person
  • Prof. Grunert, (Uni Köln, DE), Assessor B (external), External person
  • Prof. Wagreich, (Uni Wien), Assessor A (external), External person
Publication statusPublished - 2020

Bibliographical note

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Keywords

  • Sequence Stratigraphy
  • Vienna Basin
  • Badenian
  • 3D seismics
  • Delta Evolution
  • Gross Depositional Environment Maps
  • Paleo-Danube

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