BENTHAM, PETER, RICHARD KLECKER, and JAMES PLOMER, BP Amoco, Houston, Texas, and MICHAL NEMCOK, Energy & Geoscience Institute, University of Utah, Salt Lake City, Utah

Abstract: A Structural Geologic Re-Evaluation of the Eastern Polish Carpathians

The Carpathians, Poland are a Neogene foreland fold-and-thrust belt emplaced northeastwards onto the European platform during Oligo-Miocene times. Much of the recently published structural geologic work in the Polish Carpathians has offered orogen-scale mega-regional cross-sections that are of little value to a focused sub-regional exploration effort. Two new balanced structural cross sections were constructed through the Central Carpathian Depression, crossing the entire extent of the Silesian Nappe using high quality surface geologic maps, and available well control. Published geometric and physical models were used as structural analogs to guide model construction. Two levels of structural detachment are seen within the thrust system. Although the stratigraphic section consists of interlayered siliciclastic horizons, only the Eocene-Oligocene and Lower Cretaceous intervals appear to be regionally extensive detachment planes. Typical structural traps are complexly folded, north-verging anticlines developed in the hanging-walls of thrust faults.While the lower detachment controls the formation of the main structural trends, the mobility of the Eocene-Oligocene detachment level creates significant fold disharmony. Paleocene traps, although difficult to image seismically, are likely to be larger and less structurally complex, as they lie beneath this detachment level. This work was used to guide exploration risk assessment. Implications for trap volumes, trap integrity, thermal history and fluid migration can all be derived from the resulting structural model. Importantly, if risk is to be defined within the Silesian Nappe for future exploration, this will require additional structural and improved seismic imaging in order to define structural closure parallel to the strike of the thrust system.

AAPG Search and Discovery Article #90923@1999 International Conference and Exhibition, Birmingham, England