The Pyro-GC analyser is used to perform detailed analysis (finger print) on high potential sample selected through the screening methods such as the Rock Eval analysis. It also allows the chromatography of crude oils and bitumen. Correlations between the crude oils and source rocks can be determined by comparing the chromatograms of the oil sample to the pyrograms issued from source rock and heavy compounds (asphaltens). The pyrograms of the thermovaporizable and pyrolysable compounds from source rocks or reservoir rocks can be obtained without pre-treatment of the samples. The GC unit is composed of a special Programmed-Temperature Vaporiser (PTV) injector that can perform pyrolysis on bulk sample, a cold trap using liquid nitrogen placed at the column head to ensure a good introduction of the thermovaporizable compound, a split injector for oil sample, two capillary columns and two Flame Ionisation Detectors (FID).