Regional Prospectivity of Mesozoic and Tertiary in the Eastern Adriatic and Adjacent Area

J. Scott, P. Dolan, G. Lunn

Significant areas remain underexplored in the eastern Adriatic, particularly offshore Albania. Regional geologic data from the circum-Adriatic area have been assessed, and various potential plays are recognized.

Post-Hercynian deposits in the eastern Adriatic and the adjacent external zones of the Dinarides and Albanian Hellenides may be subdivided into four facies groups. (1) Permian-Lower Triassic clastics and carbonates with some evaporites, (2) Middle Triassic-lower Tertiary carbonate platform facies with associated continental margin deeper marine sequences, (3) Upper Cretaceous-lower Tertiary flysch, and (4) middle Tertiary molasse and postorogenic Neogene sediments.

The Permian to lower Tertiary section was deposited during the complex Alpine cycle, while the upper Tertiary section is the product of post-Alpine deposition. This depositional history during markedly different tectonic regimes creates two groups of petroleum plays in the eastern Adriatic: (1) Alpine cycle plays in the Permian to lower Tertiary in the thrust-faulted and folded foreland of Adria and (2) post-Alpine plays in upper Tertiary postorogenic or late synorogenic basins.

Around the Adriatic, the post-Alpine plays have so far proved the most successful. Major production occurs in the onshore Po basin and its extension beneath the Adriatic. Some of this production is from deep Alpine-cycle reservoirs, but the bulk is from the upper Tertiary-Quaternary. Similar horizons produce onshore and offshore the central-southern Adriatic coast of Italy. Major Tertiary production also occurs to the northeast in the Pannonian basin of Yugoslavia and Hungary from Miocene and younger sequences. Onshore Albania produces significant quantities of hydrocarbons; although data are scarce, much of this production is presumably from upper Tertiary molasse or lower Tertiary flysch.

Plays in the predominantly carbonate Alpine cycle sequences have not been as successful. These are usually deeply buried where they occur beneath the late Tertiary basins. In the external Alpine zones the structural complexity has inhibited exploration. Significant production occurs in the Apulian foreland in Sicily. The Alpine-cycle flysch has also proved productive (e.g., southern Apennines and Albania). In the eastern Adriatic, only hydrocarbon shows and noncommercial pools have been discovered. but considerable potential remains.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.