--> ABSTRACT: Oil in Foreland Sourced by Thrustbelt: Insights from Numerical Stress Modeling and Balancing in the West Carpathians, by Michal Nemcok and Andreas Henk; #90906(2001)

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Michal Nemcok1, Andreas Henk2

(1) Energy and Geoscience Institute, University of Utah, Salt Lake City, UT
(2) Geological Institute, Wurzburg University, Germany

ABSTRACT: Oil in Foreland Sourced by Thrustbelt: Insights from Numerical Stress Modeling and Balancing in the West Carpathians

The West Carpathian accretionary wedge advanced northeastwards over the European Platform. Its thrust sheets comprise sediments of the Early Cretaceous rifts that evolved on a passive margin of the European Platform, the Late Cretaceous-Paleocene basins formed by rift inversion and the Eocene-Oligocene flexural basin. Geochemical analyses established a clear link between pooled oils in the foreland and the Oligocene Menilite Formation inside the wedge.

Paper presents a finite-element study of stress perturbation in evolving fault-propagation folds of the Carpathian front. Results are compared with geochemical data. Mean stress gradients developed during the early stages of fault-propagation fold development are created by strong increases in hanging walls and decreases in footwalls. The mean stress controls the pore fluid pressure generation through the relationship affected by sediment porosity and sediment skeleton and fluid compressibilities. Therefore, the mean stress perturbation patterns determined as active during the active fault-propagation folding can be used to interpret a fluid flow between mean stress maxima and minima. Fluid flow interpretations indicate a fluid flow from the wedge into the foreland during the early development stages of each frontal fault-propagation fold. Our restorations by balancing show that this mechanism was active during the late Oligocene - Early Miocene, providing a long-lasting hydrocarbon migration from the accretionary wedge into the foreland.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado