Abstract: As an important biomarker in petroleum geochemistry, oceanane in crude oil and sedimentary rock is one of the isomers of C₃₀H₅₂ and belongs to the series of pentacyclic triterpane, with an apparent peak on the m/e-191 mass chromatogram. From analytical study of samples from continental sedimentary basins, it has been found that not all crude oil and source rock of continental origin contain oceanane. The latter is present only under specific geological conditions, generally in swamps, delta and shallow lake deposits or in coal measured, and its appearance is genetically related to source materials of the humus type from higher plants. It is not found in saprolelic source rocks of semideep to deep lake origin.