PEOTOMETRIC CHANGES AS A METBOD TO EVALUATE THE HYDROGEN-RICH TYPES OF VITRINITES

Based on the detailed photometric analytical results of vitrinite photometric changes in the coals and hydrocarbon source rocks of China,the interrelations of the characteristics ofvitrinite photometric changes and coal ranks(maturity)to vitrinite types are established,and the forms and ranges of photometric changes are suggested as a new method to evaluate the hydrogen-rich types of vitrinites. In oil windows or during the bituminizationstage, clear positive photometric changes are features of hydrogen-rich vitrinites, displaying obvious increases of fluorescence intensity and "yellowward shift" of fluorescence spectra to short wavelength. The clear positive photometric changes of hydrogen-rich vitriniteshave something to do with the higher contents of flow facies among them. Using the features of vitrinite photometric changes to distinguish the types of vitrinites has importantsignificance in coking blend, the evaluation of hydrocarbon source rocks in coals and terrigenous orgnic mass and the restraint correction of vitrinite reflectance.