1. Exploration and Development ��esearch Institute��Northeast Oil and Gas Branch��SINOPEC��Changchun 130062��China; 2. College of Earth Sciences��Jilin University��Changchun 130061��China

In order to confirm the developing level of hydrocarbon source rocks of Shahezi Formation in Dongling nose belt��we have researched the abundance��type and maturity of organic matter yielded in the dark mudstone in the Shahezi Formation by organic geochemistry�� The results show that the average content of“TOC”is 2. 21%��the average potential hydrocarbon generation amount is 9. 13 mg/g��the content of chloroform bitumen “A”is more than 0. 5% and the total hydrocarbon content is greater than 500 ×10 ��6 �� Above parameters suggest the dark mudstone in the Shahezi Formation has high abundance of organic matter�� The content of inertinite is low and the content of exinite and sapropelinite is higher than that of vitrinite and inertinite�� T max is 446�� �� 462�森 Combined with the relationship of T max with hydrogen exponent and degradation index��it is indicated that the major kerogen belongs to type II 1 �� I�� The vitrinite reflectance (��o) is 0. 56% ��0. 71% which indicates the low mature to mature stage�� In summary�� we conclude that the hydrocarbon source rocks of Shahezi Formation are characterized by high content of organic matters and it is of better organic matter in type�� The organic matter maturity is almost in the stage from low mature to mature��which is medium- good in hydrocarbon source rocks for oil- forming�� The Sha- hezi Formation in Dongling nose belt has a great potential for exploration��