Trace-based and geostatistical inversion of 3-D seismic data for thin-sand delineation: An application in San Jorge Basin, Argentina

Argentina’s San Jorge Basin, which straddles the southern provinces of Chubut and Santa Cruz in the heart of Patagonia, has been producing hydrocarbons since 1907. The region currently accounts for 32% of the country’s production. The existence and early geologic evolution of the basin is due to the same rift process responsible for the opening of the Atlantic Ocean in early Jurassic times. Extensive direct faulting and local erosion accompanied the rift evolution, thereby facilitating the accumulation of chiefly nonmarine terrigenous sediments well into the early Cretaceous. At this point, Andean tectonism became a major source of pyroclastic concentration in the sedimentary column; it was also responsible for pervasive batholitic intrusions. Clastic deposition in the hydrocarbon-producing zone is characterized by thick shale laminations of lacustrine and floodplain origin, interspersed with much thinner and laterally sparse sand bodies (the hydrocarbon reservoirs).