The west rim of Ordos Basin is located in the special tectonic position between Alashan block, Ordos block and Qilian fold belt. Therefore, it is also a complicated zone in tectonic and sedimentary evolution, which is different from the central Ordos Basin. On the basis of comparative analysis of sedimentary evolution characteristics between the south segment of western Ordos and central Ordos Basin, this paper focus on the study on the relationship between tectonic evolution and gas-pool forming in Paleozoic, evaluating the favorable zones and targets of Paleozoic gas accumulation in the south segment of western Ordos. The main understanding has been made as follows: 1）Relative to the central basin, the Lower Paleozoic sedimenting ended late in the western margin, and the Upper Palaeozoic depositing began early in the western margin. It shows the characteristics of early tectonic movement mainly stretching and rifting, forming two sets of reservoir-forming assemble as for Upper Paleozoic and Lower Paleozoic. The stratigraphic thickness of the Jurassic and its subsequent tectonic layer varies greatly in the lateral direction in the western margin, affected by thrusting activity since the Mesozoic（especially the Jurassic）. The thickness difference of each tectonic layer can be more than 1 000 meters. 2）The reservoir in Palaeozoic had formed in south segment of the western margin, before the large-scale thrusting had begun. Because of the strong thrusting since middle and late Yanshan Movement, the Paleozoic strata in some areas are uplifted and stripped near the surface of the earth; It results in extensive destruction of Paleozoic gas reservoirs. 3）In the wide and gentle syncline area in nappe system, and the in-situ rock masses of the footwall of the main thrust fault, the Paleozoic strata are relatively well preserved, the fracturing degree is low, still having relatively good preservation condition. 4）Comprehensive analysis showed that the Upper Paleozoic in Shigouyi syncline, Weizhou syncline, Hongsipu syncline, and Yindongzi syncline these 4 broad synclines, as well as the Ordovician platform margin facies belt in the in-situ rock masses in the footwall of the main thrust fault of the Huianpu-Shajinzi are favorable targets for Paleozoic lithologic trap exploration in south segment of the western margin of Ordos Basin.
Bao Hongping Shao Dongbo Wu Chunying Li Wei Cai Zhenhong Song Wei. The structural characteritics of south segment of western Ordos thrust belt, and its influence on gas reservoir forming of Plaeozoic[J]. Chinese Journal of Geology, 2018, 53(2): 434-457.