Eight petroleum samples from Potiguar Basin were submitted for determination of saturated biomarkers by gas chromatography (fingerprint), liquid chromatography (saturates, aromatics, resins and asphaltenes), gas chromatography-mass spectrometry (GC-MS), nickel and vanadium by high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). The geochemical parameters provided information on type of depositional paleoenvironment in which organic matter that gave rise to each oil sample and level of thermal maturation reached by generating rocks that make up the Potiguar Basin were deposited. The relationships between the stable isotopes of carbon (δ13C) and between Ni and V concentrations of each petroleum sample were also evaluated. The evaluations separated for oil samples into two distinct groups. Group 1 formed by samples P1, P2, P5 and P8, with characteristics of generating rock that was deposited in a marine hypersaline environment. Group 2 composed of samples P3, P4, P6 and P7 with freshwater lacustrine depositional paleoenvironment, which were elucidated through the geochemical parameters studied. The hierarchical cluster analysis was presented as promising chemometric tool for characterization of petroleum samples in the according to their origin of the generating rock by ratio parameters of hopane/sterane , tetracyclic polyiprenoids/diastereomers and diastereos R+S/cholestane R+S.

Reservoir geochemistry has been effectively used to evaluate compositional heterogeneity in petroleum reservoirs by employing oil fingerprinting technique to assess reservoir continuity, primarily in paraffin oil accumulations. In-reservoir biodegradation has resulted in vast deposits of heavy oils globally; therefore, the application of reservoir geochemistry to such accumulations becomes necessary. We recommend the use of pentacyclic terpanes instead of lower molecular compounds, which are less resistant to biodegradation. Using oil fingerprinting technique in this novel way enabled the differentiation of oil composition among sedimentary facies of tar sands (Pirambóia Formation, Paraná Basin).