--> Abstract: Seismic Stratigraphy, Paleogeographic Reconstruction, and Petroleum Potential of Pannonian Strata (Upper Miocene-Lower Pliocene), Southeast Hungary, by P. Varnai; #91012 (1992).

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ABSTRACT: Seismic Stratigraphy, Paleogeographic Reconstruction, and Petroleum Potential of Pannonian Strata (Upper Miocene-Lower Pliocene), Southeast Hungary

VARNAI, PETER, University of Colorado, Boulder, CO

A sequence stratigraphic study of the Pannonian basin of southeast Hungary (including the Bekes basin, Hod-Mako trough, and Battonya-Pusztafoldvar high) indicates a complex fill history during the late Miocene-early Pliocene. Analysis of 1700 km of multifold seismic data and 20 exploration wells has delineated 20 units that reflect the final deltaic progradation and filling of the lacustrine Pannonian basin. Lacustrine environments included deep-basinal marls and turbidite systems, slope and prodelta clinoforms, delta front, delta plain, and alluvial plain. Most progradation occurred in brackish to fresh water. The average water depth of the lake gradually decreased from 300 to 0 m as the basin was filled.

Rapid basin subsidence and high sediment input were characteristic during deposition of these units. Most of the strata were derived from the northwest, although there was southward progradation during the early stage of basin fill and significant northwestward progradation during late basin fill. These different, alternating sediment input directions generated complex, interfingering stratal patterns. Deposition of these units is primarily controlled by the lobe switching of different delta systems and partly controlled by changes in lake level. The thickness of the individual units gradually decreased during the infilling from 350 to 50 m.

The study area is one of the largest petroleum producing areas of Hungary. Producing reservoirs are in fractured basement with overlying deep-basinal marls, turbidite sandstones, and delta front and distributary channel sandstones. Organic-rich Miocene deep-basin marls are thermally mature and are considered to be the major petroleum source rocks in the area. The most promising stratigraphic traps in the area are associated with distal onlap of conglomerate units, compactional drape over basement highs, sublacustrine fans, and distributary channel deposits. Maturation and migration studies indicate that there is high potential for petroleum accumulation in these stratigraphic traps.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)