Late Miocene Deltaic Fill of the Pannonian Lacustrian Basin, Hungary; Its Implication to Stratigraphic Architectures and Reservoirs

Istvan Csato, Christopher G. St. C. Kendall

1. Sedimentation in the Late Miocene

In the Messinian, the Pannonian Basin was separated from the Mediterranean, forming a brackish lake between the Carpathians and Dinarides. Detailed sequence stratigraphic analysis of the Pannonian basin revealed that sedimentation was affected by a drastic paleogeographic reorganization.

2. Computer simulation and stratigraphic architectures

The complex sedimentary fill of the Pannonian lake was expressed by prograding deltaic complexes which advanced simultaneously from different directions into the basin, interfingered with each other while their spatial positions and significance changed with time. Multiple 2D computer models which simulate this fill of the basin suggest that the Messinian event stopped the major rapid sediment influx from the NE which shifted to the NW. Thick lowstand systems tract sediments accumulated along the NE slope The simulations also suggest that the basin exhibited different subsidence histories for the Pannonian subbasins. Stratal architectures were defined and simulated tying them to basin physigraphy, distance from the margins, subsidence, relative lake level change and types of sediment source.

3. Reservoirs

The different subsidence behaviors throughout the basin, and facies distribution affected fluid flow pathes, creating possible reservoir facies for hydrocarbons. As indicated by the many hydrocarbon pools of the area, the Messinian unconformity is an important surface above which hydrocarbon were trapped. A variety of stratigraphic traps occur at the interfacing zone between different deltaic systems.

The stratigraphic and exploration results of the study may be extended to other regions affected by the Messinian event.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995