| Langgu Depression located in Jizhong Depression of Bohaiwan basin, which is a paleogene graban resting and extend nearly north-east ward, the fault system of Langgu Depression is complexed, Daxing fault in the west of the Depression controlled the structure framework.Through the large scale exploration of more than 20 years, it is founded the shape of Langgu depression is rather good and the trap with great area shallow good qualification hydrocarbon-generation are drilled .Therefore it should increase the dense of survey and carry out the new area of oil exploration. It is of great target to next oil&gas exploration.The exploration proved that the study of stratigraphy sequence and sedimentary system is the key tache. while the study is only limited into the mode of partial layers and some tough mode that it can not be content with the need of exploration of hidden trap. Therefore some study of stratigraphy sequence need to be carried on. Through the sort of sequence system system tract and correction of transform ,the isochronous framework of sequence unit is established.Based on analysis of seismic section , well-log and core rocks, the framework of sequence stratigraphy is built, the strata of paleogene in Langgu Depression can be divided into 1 first-order sequence, 3 second-order sequence, 11 third-order sequences.On the basis of the framework chronostratigraphic sequence, there are 5 kind interface type of sequence be found, orogeny angle unconformity, intense angle unconformity, erodible unconformity, erodible unconformity in underwater, exposure unconformity.The types of sedimentary facies of the strata of paleogene in Langgu Depression are abundance, seven types of sediment can be identified in this work: alluvial fan, braided stream, fan delta, braided delta, sub-fan near fault, sub-lacustrine fan. shallow-lake mainly formed in the period of sequence 1 to lowstand systems tract of sequence 3, and braided delta, fan delta, sbu-fan near fault formed, deep-lake...
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