Abstract
The project focused on the construction and numerical modeling of a regional structural profile, extending from the offshore pre-Apulian zone in the west to the onshore Ionian zone within the External Hellenides in the east. A complex fold-and-thrust belt characterizes this part of NW Greece. Such type of mobile belt
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is likely to potentially host considerable petroleum reserves, and constitutes an attractive target for exploration.
Seismic data and geological maps have been used to construct the present-day section and to infer the type and timing of structural deformation and sequence of thrusting. The first step consisted in balancing and restoring the structural section into its initial, pre-orogenic configuration. Kinematic and thermal modeling was subsequently performed to constrain the main episodes of structural deformation, source rock maturation and hydrocarbon migration, and better predict the current petroleum potential of the studied area. Direct extrapolation from the sedimentary thicknesses preserved in synclines, paleo-thermometers such as Tmax and Ro, and 1D basin modeling on selected wells provided crude estimates on the thickness of eroded series. Different numerical tools such as Kine2D, Dynel, Temis and Openflow, have been sequentially used to perform the kinematic, thermal and petroleum modeling along the studied cross section.
Most significant prospects in NW Greece can be found in areas with good potential structural traps such as folded and faulted anticlines, being sourced by Mesozoic source rocks. Other areas with good trap potential are those with hanging wall anticlines, formed by high-angle faults, situated in a broad syncline below the flysch cover.
The main potential source rocks are: Triassic shales, which reached the oil window during Upper Jurassic; Jurassic Posidonia beds reaching the oil window during Serravallian; and the Cretaceous Vigla shales reaching the oil window after Serravallian times. The main potential reservoirs are situated in carbonate sequences of Triassic, Jurassic, Cretaceous and Paleogene age, which are being sealed by Neogene flysch sequences and local Triassic and Jurassic evaporates.
Beneath the major thrust-sheets deep compressional structures are expected (duplex structures), being the main objective for sub-thrust exploration. However, for the deep un-calibrated formations significant uncertainties remain regarding the exact depth and thickness of the respective sequences. Further analysis could also focus on the eastern extension of the fold-and-thrust belt. This area underwent a different tectonic regime during Cenozoic times than the selected part of NW Greece covered by this current study. This could have resulted in different structures and therefore could affect the petroleum system analysis.
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