A PRELIMINARY STUDY ON PETROLEUM ACCUMULATION IN THE QOM BASIN, IRAN

The Qom Basin was developed in Mesozoic and Cenozic on the Precambrian metamorphic base.The analytic results of organic abundance,organic type,hydrocarbon-generating evolution of source rock and oil-source correlations indicated that Shemshak Formation (Jurassic) are effective source rocks.And Qom Formation (Oligocend-Miocene) are potential sources rocks.For the Shemshak Formation,organic matters entered into oil window in the Early Cretaceous,and were evolved into wet gas and condensate zone in about 17 Ma.At the Early Pliocene (about 5 Ma),the rapid subsidence of Qom Basin brought on the over maturation of Shemshak Formation.Study of accumulation conditions showed that Qom Basin was in favor of the formation and development of petroleum system.In Qom Basin,there might be hydrocarbon accumulations with traps formed in Neogene and sourced from Shemshak Formation (and Qom Formation),there also might be accumulations with reservoir rocks and source rocks both were Shemshak Formation.