Source Rocks in the Adriatic Area and Southern Apennines: Possible New Plays

Alberto Riva, Raffaele Di Cuia, and Mara Marian

A revision on the distribution of the source rocks and plays in the Adriatic Sea and in the Southern Apennines based on the existing available data and 1D basin analysis, allowed us to better identify the existing plays, the source rock extension and possible new plays.

The two main proved plays are represented by the biogenic gas in the Pliocene-Pleistocene sequence and by the oil and gas in the Cretaceous to Miocene carbonates.

In the Pliocene-Pleistocene play type, the reservoir is represented by turbiditic sandstones deposited mainly along the axis of the Plio-Pleistocene foredeep of the Apennines. The background basinal deposition and the finer portion of the turbidites provides very effective seals. The source rock with kerogen type III is within the same turbiditic sequence and could generate biogenic gas. The traps are represented by the external structures of the Apennine thrust belt or by differential compaction over Mesozoic structures.

The Cretaceous to Miocene play type is mainly characterized by heavy to light oils generated by lower Cretaceous intra-platform sequences deposited in anoxic conditions, Lower Jurassic basinal anoxic deposits or by upper Triassic carbonate/evaporitic sequences with high organic content. The reservoir is represented by Upper Cretaceous fractured carbonates (low matrix properties) or by the Eocene and Upper Cretaceous karstified limestone underneath the main Miocene unconformity. The seal is represented by the fine-grained clastic sequence belonging to the lower part of the Pliocene sequence. The hydrocarbon accumulations are mainly trapped in horst-type structures or partially inverted blocks.

A new partially proved deep play has been identified and is sourced by hydrocarbons generated in the Middle Triassic limestone sequence with mixed sabkha and anhydrite facies. If confirmed this new play may open new exploration opportunities related to structural highs at Triassic levels in the eastern part of the basin.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013