Simulation Of Pool-forming History Of Paleogene In Tangyuan Fault Depression

In order to study the petroleum accumulation rules of the Palaeogene and restore the pool-forming dynamic process in Tangyuan fault depression.By comprehensively applying regional geological data,drilling,logging,seismic,testing data and basin modeling techniques,the basic conditions of the petroleum accumulation are analyzed and summarized,the history of the pool is restored and the pool-forming dynamic process is studied in the formation of the Palaeogene in Tangyuan fault depression.The research results are as follows,the palaeogene hydrocarbon source rocks are overall middle-good type,whose kerogen type is IIB-III,and they are in a stage of low mature to mature stage and had entered the hydrocarbon generation and expulsion threshold.Sandstone reservoirs are widely distributed,and its physical property belongs to medium porosity and mediun permeability.The closed condition of cap rocks is better and there are the multiple source-reservoir-cap assemblages and structural trap with the better preservation condition and the basic conditions of the petroleum accumulation in research area.Studies have shown that Tangyuan fault depression had entered the faulted period since the Cenozoic,the basement of basin began to rapidly subside,sedimentation rate increased gradually and it was maximized in the sedimentary period of Baoquanling formation,185.3m/Ma.The basin inversion and lifting and erosion of strata occurred at the end of sedimentary period of the Member 2 of Baoquanling formation.The fault had died out since Neogene,the scope of subsidence declined and sedimentation rate was 14.1m/Ma.The structure in Tangyuan fault depression feature in long-term inheritance development.And the primary traps were initiated at the end of sedimentary period of the Dalianhe formation and finalized in early of Neogene.The main hydrocarbon source rocks reached hydrocarbon generation thresholds in the sedimentary period of Baoquanling formation,they became mature and generated a great deal of hydrocarbons at the end of sedimentary period of the Member 2 of Baoquanling formation and began expelling hydrocarbons in the early to middle of the sedimentary period of Baoquanling formation.The hydrocarbon accumulation period of Tangyuan fault depression have two stages,the first is in the sedimentary period of Baoquanling formation and the second is in the sedimentary period of Fujin formation of Neogene.The period of trap formed is earlier than the period of hydrocarbons migration so the matching relation is proper.