Source Rocks in Ionian Zone, western Greece. Discoveries and revisions from an outcrop study

Summary An extensive potential source rock sampling survey was conducted in Ionian Zone, Epirus region, western Greece. Several samples were collected from the known potential source rock intervals (Triassic formations, ‘Lower Posidonia Shales’, ‘Upper Posidonia Shales’, ‘Vigla Shales’) as well as from new intervals showing promisin g source rock characteristics (dark color, clay content etc.). The samples were examined by organic geochemical means using the Rock-Eval 6 instrument by Vinci Technologies, France. Concerning the known potential source rock intervals, the ‘Lower Posidonia Shales’ show generally good petroleum potential, ‘Upper Posidonia Shales’ show no hydrocarbon potential, ‘Vigla Shales’ show fair to good petroleum potential but only in one locality. Several Triassic black carbonate samples are considered as ‘spent’ source rocks except from one sample showing fair petroleum potential and immature organic matter. A new potential source rock was discovered at the base of the Jurassic sequence showing very high amounts of TOC wt.% Type I/II immature organic matter with a ver y high remaining hydrocarbon potential. Oligocene-Miocene clastics show generally low TOC values with low gas potential, whereas contain very sparce, cm-thick organic-rich and oil-prone seams.