METHOD FOR EVALUATING MATURITY DEGREE OF ORGANIC MATTER OF LOWER PALAEOZOIC MARINE SHALE

The present invention discloses a method for evaluating a maturity degree of an organic matter of a lower palaeozoic marine shale, and relates to the field of petrophysical studies. The method includes the following steps: determining a conversion relation between a random reflectivity and an equivalent vitrinite reflectivity based on a heating and pressing simulation experiment and a data fitting method; acquiring a sample to be detected, and polishing the sample to be detected to prepare a polished section; observing microstructure compositions of the polished section to determine a graptolite dermatosome or protobitumen in the polished section; determining a target random reflectivity of the sample to be detected; and calculating the equivalent vitrinite reflectivity of the sample to be detected according to the target random reflectivity and the corresponding conversion relation to evaluate the maturity degree of the organic matter of the shale.