The La Luna-Misoa(!) petroleum system covers an area of about 47,500 km² and contributes more than 98% of the total recoverable oil reserves of 52.20 billion bbl and gas reserves of 51.97 tcf in the Maracaibo basin. The system developed in two phases, with each phase having the characteristics of a unique petroleum system but both sharing the Upper Cretaceous La Luna source rock. The development of each phase is related to two separate mature to overmature pods of the La Luna source rock. Biological markers indicate that the oil in this system is correlated to the oil-prone type II kerogen of the La Luna Formation, a marine source rock. Reservoir rocks of Eocene and Miocene age are the most important, contributing 50% and 44%, respectively, of the total recover ble oil in the basin. Based on average TOC content and consumed hydrogen from hydrogen indices, the mass of hydrocarbons generated by the La Luna source rock is 2.50 10¹⁴ kg and the in-place hydrocarbon in known oil fields is estimated at 352.25 10¹¹ kg. These calculations indicate that 14% of the hydrocarbons generated from the La Luna source rock actually accumulated in known traps.

The Orocue(.) petroleum system, located in the southwestern part of the basin, contributes less than 2% of the total hydrocarbon reserves in the basin. It covers 10,500 km² and encompasses the mature to overmature pod of Paleocene Orocue Formation, a coaly source rock containing type III kerogen and genetically related oil accumulations. Some of these accumulations contain a mixture of oils from the Orocue and La Luna source rocks.