The intricate basins (Kura and Rioni) located between the Greater and the Lesser Caucasus are the site of several hydrocarbon fields. In eastern Georgia, the Samgori field in the western end of the vast Kura basin extends into Azerbaijan. It is the largest hydrocarbon discovery in Georgia, with a cumulative production of more than 250MbO. In western Georgia in the western and southern Rioni, only small size fields have been discovered (East Chaladidi, Supsa or Shromisubani, a few MbOE produced). The ingredients of the petroleum system belong to the Tertiary : source rocks from the Maikop formation, siliciclastics and volcanoclastics reservoirs, shaly intervals as cap rocks, and Neogene structures linked to the structuration of the Greater and Lesser Caucasus fold belts. The Mesozoic series in the Kura basin constitute a speculative hydrocarbon target to be explored in the future although at greater depth below the Tertiary folds. In the Kartli sub-basin at the western end of the Kura basin, there is only scattered and often over-matured Mesozoic series to look for source, reservoir and cap rocks analogs. In the Rioni basin, less mature Mesozoic series crop out, offering a possible evaluation of all the geologic elements and processes essential to an hydrocarbon accumulation. A preliminary investigation of the Mesozoic series revealed several organic rich horizons, reservoirs and cap rocks in the pre Cretaceous series. This leads to propose a schematic pre-Cretaceous paleogeography constituting the base for defining possible petroleum systems. Preliminary organic geochemical analyses of organic-rich horizons lead to identify several layers having fair to moderate hydrocarbon potential for oil and gas. Based on this preliminary result, information derived from bibliography and published seismic lines, and 1D modeling with Petromod software lead to propose new potential plays in the Rioni basin. This speculative study requires new biostratigraphic studies to confirm the ages of the various identified organic rich horizons, some of them being possibly new to refine the modelings. More detailed fieldwork should focus on reservoir quality and distribution. Eventually, analysis of reprocessed seismic data will permit to confirm new petroleum thematics.