| The Linnan low-laying which is on the westward of Jiyang Depression ,is the hypo-grade tectonic cell of Huimin sag .In northern of the low-laying the tectonic zone of Lin-Shang fault assembled abundant oil & gas ,meanwhile the igneous rock structure and the southern slope of the Low-laying also formed industrial oil & gas field . Along with the of oil gas prospecting , the rate of finding big and middling oil gas reservoirs become less and less , moreover the proportion of subtle reservoirs will be more and more . Therefore the empresses of prospecting turn from big and middling constructional oil gas reservoirs to medium and little sized structural-lithologic subtle reservoirs .The E2S4 of Linnan low-laying mainly develops clastic volcanic and a suit of siltstone and thin sandstone / mudstone interbeds which is shore shallow lake sedimentary facies . Because of the less well exploration ,it is an issue being cared whether there is good source rocks sediment in the pass. On the face of the sedimentary environment of E2S4, there are good conditions for forming valuable source rocks in Linnan low-laying .This text using the sequence stratigraphic methods do research to the depositional system framework.,make clear the distributing of sand body in room and open out the generation potential ,so that to provide instruction for the subtle reservoirs in Linnan low-laying.The researching method of this investigation is that ,fist of all , basing on the seismic reflection character and uniting the well log data ,ancient biology data ,and core data ,identify the sequence boundaries , make off sequences and tracts and found the sequence stratigraphic framework .Secondly, according to the well log data such as spontaneous potential and apparent resistivity , divide the parasequence adding manner ,distinguish RST(regressive system tract),HST(highstand system tract),TST(transgressive system tract),do well contrasting sign with the parasequence boundaries .Finally using core data, well log data, granularity analysis data , and flick analysis data to do single well facie analysis in pivotal well . Relying on the analysis of the sedimentary facies , parafacies of every parasequence set , investigate the depositional system and do analysis to the hydrocarbon generation condition and formation conditions of reservoir in the stratum.According to the seismic data and well log data divide the upper E2S4 of Linnan low-laying into a third class sequence whose type is T-R cyclic sequence–including lake transgression and lake regression tracts. The dark mudstone of E2S4 in Linnan low-laying mainly distribute in the upper E2S4 which is shore shallow lake-semi crater lake sedimentary facies. Organic matter type is moderate to good source rocks. From the edge of depression to the center of depression the upper E2S4 source rocks divide into low maturity zone, normal maturity zone, high maturity zone, differently form immature oil, normal oil, light oil indeed condensate and moisture . The dark mudstone of E2S4 has the course of hydrocarbon generating both in S1-Dongying period and later tertiary. It is the primary hydrocarbon generating period in which in prophase generated a little low maturity and in anaphase generated normal maturity and high maturity. And base oil generating is really appearing in E2S4 source rocks. Through basin simulative account, we can know the oil resource quantity is 0.8367×108t and the gas resource quantity is 47.1074×108m3 ,oil gas resource quantity is 0.8838×108t . We can get the conclusion that there are many formation conditions of reservoir such as plenteous oil sources, multi reservoir and advantaged leading system. And it is the most important aim tier for prospecting in future.
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