Study On Hydrocarbon Accumlation Period And Simulation Of Pool-Forming History In Yanji Basin

In order to study the petroleum accumulation rules of the Cretaceous and to provide thescientific basis for the optimization of exploration areas in Yanji Basin, the pool-formingperiod was determined by depending on fluid inclusion testing technology.And the history ofthe pool was renewed,and the pool-forming dynamic process were studied by basin modelingtechniques in this paper.The research results are as follows,the Cretaceous in Yanji Basinhave been in development of fluid inclusions which have two stages and these correspond totwo accumulation stages. The fluid inclusions contain hydrocarbon（sCH4and C6H6）and non-hydrocarbons,such as CO2and N2etc.The structural traps in Yanji Basin feature in long-terminheritance development.And the traps were initiated during the deposition of the Tongfosiformation and finalized during late Longjing stage.The tectonic movement which occurred atthe late stage of Longjing resulted in the erosion of formation.And the denudation inChaoyangchuan Depression began later than that in Qingchaguan-Dexin Depression and theerosion thickness in Chaoyangchuan Depression is less than that in Qingchaguan-DexinDepression.The heat flow is high during the faulting period while it is low duing thedepression period in Yanji Basin.And because of the magmatic intrusion,the geothermal fluxincreased about0.4HFU during late Longjing stage. The primary hydrocarbon accumulationbegan during the deposition of the first and second members of the Dalazi formation inQingchaguan-Dexin depression while it began during the deposition of the third member ofthe Dalazi formation in Chaoyangchuan depression. And the main periods of hydrocarbonaccumulation is the sedimentary period of the third member of the Dalazi formation inQingchaguan sub-depression while it is the sedimentary period of the Longji formation inChaoyangchuan depression and Dexin sub-depression.The hydrocarbon accumulation indifferent sags and sub-depressions of Yanji basin ended in Paleogene and it was suchpreserved.The Tongfosi formation of the GOI>5%is the major formation for the petroleumassemble in Yanji basin. And the Qingchaguan sub-depression,which has the highest value ofGOI(GOI=9.6%), is the favorable oil exploration region.