Abstract: Basing on detailed test data of the Damingtun depression, the main charging pathway of two petroleum system is reconstructed by means of hydrocarbon compositional heterogeneity. Migration tracing results are nealy the same based on hydrocarbon bulk compositional heterogeneity, molecule construction heterogeneity and the distribution of nitrogen compound respectivly. It clearly shows that both normal oil and highwaxy oil were migrated to the the slopes from the centre of hydrocarbon kitchen of depression centers and were enriched in the reservoirs of the favorable traps. Some reservoirs could be formed on the pathways of the petroleum system only if only some favorable traps are met. Hence the present research could provide some information for the reservoir targets. K-Ar dating technique shows that the major pool forming time of the Daming sag is from the Sa1-2 to the early Dongying period. The pool forming time of the Anfutun sag is earlier than that of the Rongshenpu sag, which indicates that the highwaxy oil is earlier than the normal oil.

Key words: hydrocarbon compositional heterogeneity, K-Ar time dating technique, migration and accumulation history, Damintun depression