Abstract:

There developed several structure oil/gas traps or structurelithology oil/gas traps in  delta deposit of Eogene Shahejie Formation and Dongying Formation, Hongxing area. Because of the longalive activity of Jiazhangsi fault, structure or structurelithology oil/gas traps were obviously controlled by Jiazhangsi fault and its associated faults. The study shows that the source rock of Sha 3 Member of Shahejie Formation developed extensively in Jiazhangsi sag, and the system tract of 3rd order sequence or subdistibutry, mouth bar, delta front sheet sandy and transgrasive lacustrine mudstone of 4th order sequence formed 7-8 trapscale reservoir and seal combinations in Sha 1 Member of shahejie Formation and Dong 3 Member of Dongjing Formation, which constitute the basic condition to oil/gas trap. Synsedimentary fault controlled the development and distribution of sandbody. The western fall part of Jiazhangsi fault and NEE direction extended associated faults controlled the sandy distribution developed in different periods. Longalive activity of Jiazhangsi fault connecting to reservoir sand formed the major oil/gas transfer system, along which there formed favorable structure or structurelithology oil/gas traps. Especially, the earlier developed deep senior associated faults make great significance to oil/gas distribution and oil/gas trap development. Most of these senior faults didnt develop in the upper of Sha 1 depositional period, so that oil/gas transferring along these faults tended to assemble at the middle of Sha 1 Member of Shahejie Formation. There was a good combination of reservoir and sealing, and that is why there extensively developed oil/gas trap in middle of Sha 1 Member

Key words: structurelithology oil/gas trap, trapping study, controlling factor, Eogene, Hongxing area