Structural Characteristics and evolution of the main structures of the east area of the Wushi Depression,Beibuwan Basin

Abstract:

Affected by multiple stages of tectonic movements,the Wushi Depression of the Beibuwan Basin has formed complex internal structures.Accurately identifying the structural development characteristics of different stages has a great significance for oil and gas exploration. In this paper, we use the high-precision 3D seismic、well data to analyze the fault characteristics,structural styles,and the evolution history and formation mechanism of the main structures.The analysis results show that under the influence of the extension-strike-slip-weak compression stress fields,which is triggered by the the interaction among the Pacific plate, the Indian plate and the Eurasian plate,three sets of structural systems in the eastern area of the Wushi Depression were developed and 13 types structural styles were identified.The formation of the fault systems endured five main stages,including the initial weak rifting stage in the Paleocene,the main extension stage in the Eocene,and the strike-slip and weak extension stage in the Early and Middle Oligocene,the strike-slip and weak compression stage in the late Oligocene,and the final stage since the Neogene.