Five different oil shale kerogens were analyzed with advanced testing techniques (XRD

13C NMR and FT-IR) to obtain important structural information. The long-range disordered state of aggregation was also confirmed by XRD. Using 13C NMR spectroscopy

18 characteristic parameters of carbon skeleton structure were obtained. Detailed information about the chemical structure of kerogen was obtained through verifying the results of 13C NMR experiments with the qualitative analysis of kerogen groups made by FT-IR technique. The aliphatic structure of oil shale kerogen was up to 60%—90%

with the methylene carbon occupying the dominant position of 77%—90%

and most of the aliphatic structure were straight-chain while less alicyclic or branched chain. In addition to Huadian oil shale with a monocyclic aromatic carbon structure

the other four oil shale kerogens were co-existing monocyclic and polycyclic rings

with the latter mainly peri-condensed. The oxygen structure was C-O (alcohol

phenol

ether) and C=O

and carboxyl class was more than carbonyl class C=O. More C=O in kerogen was due to a low degree of metamorphism

while a high degree of metamorphism resulted in more C-O.