Geological Probability of Success (POS), case study in the Late Miocene structures of the western part of the Sava Depression, Croatia

Geological probability calculation was applied to the Northern Croatian Neogene deposits in the western Sava Depression. Structures “A” and “B” (with sandstone hydrocarbon reservoirs inside the Kloštar Ivanić Formation, Upper Miocene) were analyzed using two different Probability of Success (POS) methodologies. The classical POS approach showed that, in such play and wider areas of selected two structures, the probability for discovering the new HC reservoirs is 42.18%. This is valid for minimum of 500,000 m 3 of geological reserves. The modified POS approach has been used for calculation of waterflooding efficiency in selected structures “A” and “B.” The probability value of 56.25% indicates that future flooding would result in increased recovery.