Structural Styles Of Mingjiang Depression In The East China Sea Shelf Basin And Their Significance For Petroleum

East China Sea Shelf Basin is a Mesozoic-Cenozoic superimposed basin located in the East China Sea continental shelf.During the past 50 years,the exploration in the Cenozoic strata has obtained great break through,whereas the Mesozoic has no oil and gas breakthrough.At present,the basic geological research is weak and the data is scarce.The formers believe that Minjiang depression has great potential of oil and gas resources in the Mesozoic,we need a systematical summary of the Mesozoic structural style,fault distribution and experienced tectonic movement,from the structural features to forecast Mesozoic oil and gas prospecting area.The Minjiang depression is located in the southwest of the East China Sea shelf basin,with a wide distribution and large thickness.According to the seismic reflection characteristics,Minjiang depression is divided into 5 seismic sequences,5 seismic reflection interface respectively corresponding to the 5 regional unconformity,respectively representing Longjing,Oujiang,Yandang,Yushan and Jilong structural movement.Yandang,Yushan and Jilong structural movement has great influence on the evolution of the Minjiang depression.According to the different tectonic stress,tectonic style of Minjiang depression will be divided into 3 categories: extensional tectonic style,compressional tectonic style and complex tectonic style are further divided into 3 categories,such as Horst faults,Grabens,Volcanic structures,A half graben,Compressional anticlines,fault-related anticlines,Flower-like structures and Inverse structures.The fault is the basis of basin analysis,Minjiang depression mainly develops three main fault: Yandang fault,Taipei fault and North Huyan fault,this three main faults controlled the tectonic pattern of Minjiang depression.FZ13-2-1 well and FZ10-1-1 well reveal that the source rocks of Fuzhou formation has good potential,and the reservoir,caprock and preservation conditions are good.From the the structure features to research,various types of oil and gas reservoirs are controlled by the tectonic styles and faults of the basin.Presumably,the Jilong-Xinzhu depression is the main oil source depression,Minjiang-Xiapeng slope is the migration direction of oil and gas,and local tectonics developed on slope are favorable area for oil and gas accumulation.