Study On Migration Pathway And Hydrocarbon Accumulation In Minfeng Faulted Zone Area

This paper synthetically utilizes geological, geophysical and geochemical data as well as previous research achievements to study the petroleum migration pathway system characteristics of Paleogene Shahejie Group in Minfeng faulted zone area and study the main controlling factors of petroleum accumulation in the study area and establish the hydrocarbon migration and accumulation model.The migration pathway of Shahejie Group in the study area is consisted of conducting elements such as fault and sandstone, which form the fault-sandstone migration pathway system. Minfeng faulted zone developed a set of faults which mainly strike in the direction of NWW—SEE and parallel to each other which constitute a NWW—SEE faulted zone among which there are 5 source faults. Due to the fact that these faults are small in scale and fault only the relatively shallow layers and the fault activity is weak during the later stage, its petroleum migration power is relatively weak. The turbidite sandstone in Es4, Es3 zx only develop in local area which are thin in thickness and is poor in connectivity and can only be used as reservoir sandstone. The delta and fluvial sandstone in Es3 s and Es2 develop well, and the thickness of single sandstone layer is relatively thick and the sandstone connectivity is well which can not only be used as reservoir sandstone but also as conducting sandstone. But its connection with source rocks is poor and only those sandstone which develop in the better connected area is advantageous. The faults connect well with Es3 s and Es2 sandstone and are favorable for the lateral hydrocarbon migration.The oil and gas in the petroliferous Yong 12 fault block which lies in the east part of the study area is migrated from Yong 3 fault block to the east part of the study area. The oil and gas originate from Minfeng sag firstly migrated to Yong3 fault block which is the main part of Yonganzhen oil field and separate around the northbound fault and flow along the fault and sandstone to Yong 12 fault block and is accumulated there. Comprehensive study shows that the controlling factors on petroleum accumulation in the study area are migration and trap conditions, the area where develop good migration and trap condition is rich in oil and gas while the main faulted zone area is poor in oil and gas restricted by its poor migration and trap conditions. Comprehensive analysis shows that the area which develop good trap in the south of fault 10, the Es4 s and Es3 x sandstone developped area and the sandstones of Es3 z in the slope area which are connected to the source rock by faults are the favorable area for future exploration.