Hydrocarbon Exploration Risk Assessment in Structurally Complex Areas. Examples from Western Greece

Hydrocarbon exploration in structurally complex areas such as Western Greece requires good understanding of the main uncertainties controlling the petroleum systems and its associated risks. In the case of the external zones of the Hellenides Fold Belt such complexities are dominated by the presence of Upper Triassic evaporitic units that represent the regional detachment of the thrust sequences. The presence of salt in this fold belt exerts an important control on the structural style and, therefore, the structural play type. In basin and petroleum systems analysis, the reconstruction of the burial history is decisive to assess the quality of source, reservoir and seal rocks. With this purpose, and in order to better understand the main uncertainties present in the area of study, sensitivity analysis of the eroded thicknesses occurred in the Ionian zone during compression and uplift in the Miocene has been performed using maturity data at different locations. These erosion estimates allow constraining the restoration of structural sections and a better 2D analysis of the burial history of the area. In the Ionian zone, and due to tectono-stratigraphic variations from north to south, the assessment allows discerning between areas with different timing of hydrocarbon generation and potential trap charge.