Arcuate fold-thrust belts and its oil gas exploration prospect in the northern Qilianshan
Du Wenbo1，Zhang Jinjiang2，Xiao Yuxiang1,3，Zhang Bo2，Li Xiaojun1，Hou Xiuliu3，Wang Meng2，Li Jing1，Cheng Guangjin1
1.Exploration & Production Research Institute，Yumen Oilfield of CNPC，Jiuquan，Gansu 735019； 2.The Key Laboratory of Orogenic Belts and Crustal Evolution，School of Earth and Space Sciences，Peking University， Beijing 100871；3.Exploration & Production Research Institute，CNPC，Beijing 100083
The northern Qilianshan thrust belt in the southern Hexi Corridor Basins is an important boundary in the northeastern Tibetan Plateau. The belt plays a key role in the Cenozoic intracontinent deformation. Based on the field structural surveys， seismic profile interpretations and attributes of seismic data， the blind arcuate fold-thrust belts are identified under the thrust nappe in the Kulongshan-Liugouzhuang belt in the western segment of the Jiuquan Basin. Our observations demonstrate that the curved trend lines are indenter-controlled salients. The salient geometry resulted from vertical variations in basement uplifting and differential movements to foreland direction. Specifically， fracture development and distribution are response to the structural trend lines in the indenter-controlled salients. The central zone in the curved fold-thrust belt is characterized by high fractures and micro-fault networks， which is favorable area to develop fractured reservoirs.