The present study shows a preliminary evaluation of the structural style and the oil potential of the North Flank of the Venezuelan Andes, between La Fria and El Vigia.

The geologic interpretation of the seismic sections indicate that the northwestern flank of the Venezuelan Andes in the study area has been overthrust toward the adjacent Maracaibo Basin along a deep thrust fault. The resulting Andean structure has been modeled as a northwestward-verging fault-bend fold deformed over a crustal scale ramp. This thrusting began as early as Lower Miocene and was the result of major compressive forces oriented northwest-southeast. Two molasse cycles separated by a major intra-Miocene discontinuity were identified in the southwestern part of the Maracaibo Basin. This unconformity has been related to an erosive event which occurred during the Upper Miocene and apparently is associated to the uplift of the Santander Massif as a result of compressive tectonic forces oriented east-northeast west-southwest. From Upper Miocene to. the Present times, the Venezuelan Andes are being affected by northwest-southeast and east-northeast west-southwest tectonic stresses.

The hydrocarbon potential of the study area is based on the reconstruction of the oil and gas generating areas using TTI-maturity diagrams. The data used in this modeling is supported by the results of the seismic interpretation made for the study and on the petroleum geology and geochemical evaluation of the Maracaibo Basin. Two models of hydrocarbon generating areas were reconstructed for the La Luna and the Orocue source rocks. The first model (Model I), assumes in the TTI maturity diagrams that the intra-Miocene discontinuity is an important erosive event. The second model (Model II), was reconstructed assuming in the TTI calculations that the intra-Miocene discontinuity represents an hiatus. The results of both models indicate that oil and gas were generated from the source rocks of the La Luna Formation and Orocue Group. The generation of oil in the area occurred simultaneously with the Andean uplift (Lower Miocene-Present, Time). The preservation of potential oil accumulations in the Andean flank depends of the effects of meteoric water invasion into the reservoirs and the structural modification of the traps during the Andean tectonism. Based on the actual distribution of oil and gas kitchens in the potential source rocks as well as their effective drainage area, the most prospective zone for potential traps seem to occur to the north, northwest and west of the Andean trough.