The Study On Tectonic Characteristics Of Nantun Formation In Beier Depression, Hailar Basin

Hailaer basin is a large sedimentary basin in the peripheral part of Songliao basin,which is the next important place to Looking for oil and gas resources in Daqin Oilfield.Beier depression of Hailaer basin is the most promising negative secondary structuralunit, and worthwhile of further study. Beier depression is a superimposed basin formedby fault-depression in early, and down-warped basin in the after. During faulted-depression period, reforming formation influence by the ancient protrusions andbasin-controlling fault. After multi-period Large-scale tectonic movement, Beierdepression has a certain section and independence, which form the complex fractureand fault block system.The study which is based on previous research, comprehensive analysis andcollation of the existing geology, drilling and seismic data, identified and differentiatedunconformity surface, established the stratigraphic frameworks, systematically studiedthe tectonic characteristics and its evolutionary process of Nantun formation. Deeplyunderstanding the structures, characters, oil-gas migration and the oil and gasaccumulation conditions will lay the foundation for the further exploration. Throughthe thesis research, the main access to the following understanding:(1) According to the subtle seismic interpretation, through the research of theregional tectonic setting and structural style, etc, identify Beier caprock developed4first order tectonic sequences interface, which is divided into4Structural layers: the riftstructure layer(Tongbomiao Formation, Nantun Formation), the fault-depressedstructure layer(Damoguaihe Formation, Yiming Formation), Depression-upliftstructure layer(Qingyuangang Formation), the shrinking structural (cainozoic).(2) This study focus on Nantun Formation. Controlled faults are composed ofNE、NEE and NW faults. Bayantala develop NW controlled faults. In the mid area,NEE faults are master control faults. And NE faults in the south. The course of thesynsedimentary fault is NE.(3) According to the fault development, Beier can be divided into seven secondarytectonic units: West-Beier sub-depression, South-Wuerxun sub-depression, mid-Beiersub-depression, East-Beier sub-depression, Bayantala tectonic belts, Suderte tectonic belts, and Bulehongbusi uplift belt. Fault-sag structural layer can be divided into eightsecondary tectonic units: West-Beier sub-depression, South-Wuerxun sub-depression,Mid-Beier sub-depression, Northeast-Beier sub-depression, Bayantala tectonic belts,Suderte tectonic belts, and Bulehongbusi uplift belt.(4) The structures in Nantun period controlled by the NEE and the NE fractures.NNE faults controlling the formation of West-Beier sub-depression and Suderte groove,The NE faults in the south of Beier form the north and east to concave tectonicframework.(5) Through the tectonic evolution of Beier depression, there are four formativeperiod: the rift structure(Tongbomiao Formation, Nantun Formation), thefault-depressed structure(Damoguaihe Formation, Yiming Formation),Depression-uplift structure(Qingyuangang Formation), the shrinking structural(cainozoic).