Being one of the important unconventional oil resources

oil sand is well worth of geochemical study so as to better guide its resource assessment.Thirteen oil sand samples were collected from Tumuji ranch in western Songliao Basin and analyzed for oil yield

bulk composition and GC-MS.The result shows that the oil yield of oil sand is high

and non-hydrocarbon components dominate the bulk composition.Most compounds in saturated and aromatic hydrocarbon fractions were largely biodegraded.The n-alkanes

isoprenoid alkanes

hopanes and steranes were all degraded in varying degree except for tricyclic terpanes.No 25-norhopane series has been detected in the studied sample suite. The naphthalene and phenanthrene series were all destroyed but the triaromatic steroids are intact.These oils are derived from single source rock system on the basis of biodegradation resistant compound signatures.