Accurate analysis of kerogen type is important in source rock evaluation, because its chemical structure is closely related to composition of hydrocarbons generated. In this work, whole rock and isolated kerogen samples from Noshiro GS-1 well were investigated by flash pyrolysis techniques, and the products were examined by gas chromatography and gas chromatograph-mass spectrometry.
Phenolic compounds were dominant in pyrolysis products of terrestrial kerogen (woody-coaly type), whereas aliphatic hydrocarbons were major products in marine kerogen (amorphous type). The ratio of phenolics/aliphatics was well correlated to the results of visual kerogen and Rock-Eval analyses.
Pyrolysis products of whole rock samples were less amount than those of kerogen. However, the phenol/C₁₂ ratio has been suggested to be effective for kerogen typing. The results show that phenol/C₁₂ ratio of gas-prone kerogen is above 2.0 and that of oil prone kerogen is below 0.5 for both kerogen and whole rock samples.