Diamondoid and biomarker characterization of oils from the Llanos Orientales Basin, Colombia

Because of their thermal and biological resistance, diamondoids have been used to assess the thermal maturity of light oils and condensates. Combined with biomarker data, they have also been applied to the characterization of mixtures of oils with contrasting maturity levels from distinct migration pulses in a single petroleum accumulation. We analyzed 22 oils from a Colombian sedimentary basin using gas chromatography coupled with mass spectrometry (GC/MS) to identify and characterize their biomarker and diamondoid distributions. Ratios of diamondoids and biomarkers provide a more refined maturity assessment because most of the oils have been biodegraded. Our integrated interpretation of the biomarker and diamondoid data allowed us to recognize different levels of thermal maturity in the oils, as well as to consider possible mixtures of oils from distinct migration pulses.