Remaining Hydrocarbon Potential and Exploration Strategy in SW Part of Pannonian Basin, Croatia

Croatian part of Pannonian Basin (PB) has reached moderately high to high level of exploration maturity in some parts. As a consequence of that it is expected that most upcoming discoveries will be made within the small to medium size range (10 MMboe avg.). Sava, Drava, East Slavonija and northern part of Northwestern Croatia depression can be regarded as mature areas for exploration, while southern part of Northwestern Croatia, Southwest Sava and southeastern part of Sava are still under-explored areas. According to several studies, statistical and basin volumetric analysis there is still approx. 46 % of remaining hydrocarbon volumes to be discovered in PB. Past 60 years exploration period statistics also show that approximately 85 % of exploratory wells outside producing fields investigated section between 0-3500 m. Only 11 % of the wells drilled down to 5500 m. In most cases shallow portion of the sediments from 0 m to 1500 m were not addressed properly for shallow gas targets. Majority of the wells were drilled on structural traps, however latest positive INA drilling records indicate that significant stratigraphic traps potential is yet to be revealed. Deeper, less explored section between 3500 m – 5000 m is today becoming more interesting for unconventional gas reservoirs exploration but also for some conventional reservoirs.