Evolution and Petroleum Potential of the Ionian Basin (Northwest Greece)

Oil & Natural Gas / Gas Shales / Exploration

Five organic-rich formations of source-rock potential have been observed in the Ionian basin: the Vigla shales (Albian-Turonian), the Upper Posidonia beds (Callovian-Tithonian), the Lower Posidonia beds (Toarcian), the marly beds at the base of the Ammonitico Rosso (Early Toarcian), and shale fragments in the Triassic breccias. These five horizons have good hydrocarbon potential and their organic matter is of type I to II.

In the central Ionian basin (oil window = 3700-5800m), the Triassic shales have already entered the gas window; the Lower and Upper Posidonia beds and the marls at the base of the Ammonitico Rosso are mature in terms of oil generation; the Vigla shales correspond to an early maturation stage.

The preservation of the organic matter in the Lower and Upper Posidonia beds, and the marls at the base of the Ammonitico Rosso, is mainly due to the geometry of the synrift period, whereas in the Vigla shales it is also related to the Cretaceous Anoxic Events.