Abstract: Laojunmiao structural belt is located in Cenozoic foreland thrust belt in southern margin of Jiuquan Basin, which is superposed over the southern uplift and Shida sag of Early Cretaceous faulted basin. Laojunmiao Oilfield, the earliest oilfield discovered in China, lies in this structural belt. Based on synthetic research and analysis with seismic and non-seismic data and field observations, Laojunmiao structural belt is believed to have experienced Mesozoic and Cenozoic structural evolution. Vertically, it features in the superposition of multiple thrust blocks. Horizontally, it is characterized by E-W segmentation due to the division of many NNE adjusting faults, as well as the structural deformation is strong in the east and weak in the west. Discussion is made on oil/gas accumulation regulation by using drilling and logging data. The research shows that the fluvial sandstone reservoir of Palaeogene Jianquanzi Member of Baiyanghe Formation is the main exploration target of the belt, oil and gas being mainly from Lower Cretaceous source rocks of Qingnan sub-sag. According to the analysis of structural area and the evaluation of corresponding zones and traps, it is believed that Fault block 134, Miaoxi Fault block, Miaoxi anticline, and the central thrust fragments are the target for further oil and gas exploration.

Key words: Laojunmiao structural belt, structural evolution, structural feature, oil-gas accumulation, oil and gas exploration