Prototype Basin Analysis Of Dunhuang Basin During The Jurassic

Dunhuang basin, which locate in the intersection of Gansu, Xinjiang and Qinghai, has low exploration degree, so which restricts the basin oil and gas exploration and development. In the paper, on basis of the prototype basin analysis principle and interpretation of the aero magnetics in Dunhuang and surrounding areas, The Dunhuang basin is bounded by the Minfeng-Qiemo fault to west, the Hongliugou-Lapeiquan fault to the southwest, the Altun fault and the south and the east. According to the feature of China geotectonic during the Jurassic and existing deep seismic analysis, the evolution of Dunhuang basin is not only impacted by the remote effect of the continental marginal but also by the China tectonic and the plate location of basin basement and active belt. Based on the difference of paleoclimate, paleontology, sedimentary facies, the deposits colour, the lake basin area, tectonic movement phase and the regional tectonic stress field, the Jurassic is divided two structural layers:the Lower-Middle Jurassic structural layer and the Upper Jurassic structural layer. The analysis of the marginal facies and provenance indicated that the Sanweishan Mountain fault controlled the Wanyao Sag and Wudun Sag and the Altun fault controlled the whole basin. Based on the seismic time and depth transformation, we designed the residual strata distribution map during Jurassic which showed that the Lower Jurassic appear in every alone sags and had a thin thickess. During the Middle Jurassic, the scale of sedimentary stata was increasing and had a large thickness, the Wudun Sag had linked the Wanyao Sag,and the Wudun Sag is the depocenter and subsidence center on the north of Sanweishan Mountain but the Howliugou Sag did not link the Daba Sag in the south of Sanweishan Mountain. During the late Jurassic, the stata appear in the Wudun Sag, the Hongliuyuan Sag and the Daba Sag and had a bad connectivity, but the Wudun Sag is the depocenter and subsidence center...