Porosity Characteristics and Evolution in Fractured Cretaceous Carbonate Reservoirs, La Paz Field Area, Maracaibo Basin, Venezuela

The shallow-marine Cretaceous Cogollo Group in the Maracaibo Basin (Figs. 25-1, 25-2) is oil-productive from fractured carbonates of low porosity and permeability. These carbonates have been moderately folded and faulted, as recorded by seismic record sections (Figs. 25-3–25-5). Tectonic deformation, including fracturing, is particularly intense along major faults. Oil accumulations in the carbonates are localized in a large number of structural traps (Fig. 25-6).