When organic matter undergo oxidation

the compositive proportion of elements

the highest pyrolysis peak temperature

the rate of hydrocarbon conversion and vitrinite reflectance would change distinctly

the conventional distinguishing index of organic matter evolution would lose its significance.The study results of the southeast uplift in Songliao Basin show that after the oxidation of organic matter

the O/C ratio of kerogen decreases with the increasing of evolution degree

thus reulting in the reflected evolution degree higher than the actural one and increasing in T

amx

.The oxidated organic matter usually has higher conversion ratio under the same thermal condition.The reflectance of the vitrinite formed in strong oxidation condition is higher than in normal circumstance

and that in strong reduction condition reduces.Therefore

to study the evolution of organic matter in the southeast uplift

especially in Yingcheng Formation of the uplift in Songliao Basin

one could not make a conclusion according to a certain index.