Integrated, Basin-To-Reservoir Scale, Geologic and Geophysical Studies of a Carbonate-Hosted, Hydrocarbon Reservoir of the La Vela Basin, Northwestern Venezuela
The 2009 discovery of Perla field in the Gulf of Venezuela (GOV), a 17 TCF of thermogenic gas giant - hosted in a 300-m-thick, carbonate (red algae) reservoir - stimulated reevaluation of potential hydrocarbon reservoirs in Cenozoic carbonate rocks in northwestern South America. I use regional gravity and magnetic data integrated with a basin-scale database of 1100 km2 of 3D seismic data and 52 wells from the Venezuelan national oil company (PDVSA) to assess carbonate reservoirs of the La Vela Basin (LVB). The LVB produced small quantities of oil and gas from carbonate reservoirs of early Miocene age since the 1970’s and is located 100 km east of the La Perla discovery. Regional gravimetric and magnetic data, integrated with four modeled gravity profiles was used to determine the location of the suture between Precambrian and Paleozoic continental crust of South America and the accreted Caribbean arc along the Adícora-Pueblo Nuevo strike-slip fault system bounding the northern edge of the LVB. Basement in the LVB consists of three types of allochtonous, metamorphosed, basement of Neoproterozoic, Permian, and Cretaceous age. The differences between the carbonates that develop in the LVB, Falcón onshore and GOV seem to be driven by ecological, and tectonic conditions, with areas that favored the development of the red algae ramps, better reservoirs than the carbonate facies found in LVB (corals). In the reservoir-scale study of the carbonate and basement in LVB, application of the sparse layer inversion seismic method resulted an enhanced bandwidth and an improved structural interpretation of the 3D volume. Use of the sparse layer inversion volume for multiattribute analysis and prediction of acoustic impedance, density, and effective porosity yielded smaller errors and better correlation coefficients that the original 3D volume. Based on results from gravity, 3D seismic interpretation, and sparse layer inversion, I propose that the heavily, fractured area of basement and carbonate rocks north of the Adícora-Pueblo Nuevo strike-slip fault system is the most promising area for exploration in the LVB.