Hydrocarbon anomalies using airborne gamma radiation over the unconventional petroleum system of the South Portuguese Zone, Portugal.

Abstract The use of airborne gamma radiation in hydrocarbon exploration is widely known to define possible areas of microseepage. At this paper, the radiometric survey was applied to identify hydrocarbon anomalies over the South Portuguese Zone (SPZ) unconventional petroleum system. Spectral gamma-ray data were processed to thorium normalization method. Obtained results show positive anomalies mainly on the southwest sector of the SPZ, corroborating the data obtained through fluid geochemical analysis, revealing other several surface sweet spots for hydrocarbons emanations.