Structural patterns and influencing factors of the upper wall of the nappe in the Karamay-Wuerhe fault zone, northwestern Junggar Basin

Many oil and gas reservoirs have been discovered in the Karamay-Wuerhe (Ke-Wu) fault zone and its periphery in the northwestern margin of Junggar Basin. With the deepening of exploration level and geological understanding, the upper wall of nappe has already presented a situation of "Baili Oildom". However, due to the influence of multi-period tectonic activities and complex lithological assemblages inside the fault zone, the structural patterns show various types and complex spatial distribution patterns. Therefore, it is necessary to further explore the structural patterns and genesis. Based on seismic data, drilling data and regional tectonic framework, this study summarizes the structural deformation characteristics and influencing factors of the upper wall of the Ke-Wu fault zone in the northwestern margin of the Junggar Basin; the upper wall of the nappe of the Ke-Wu fault zone is divided into three deformation units: namely southern, central and northern segments; the five main tectonic stages of the Carboniferous strata on the upper side are clarified, and the stages and styles of tectonic evolution have been restored. In summary, the main factor for the difference in the original deformation of the Carboniferous inner strata is the original lithological assemblage relationship. And the difference of the lithologic assemblage in the upper wall is the main factor for the preservation of the original structure. The above factors together result in different trap conditions from south to north along the Ke-Wu fault zone. This study has guidance for future hydrocarbon exploration of the upper wall of the Ke-Wu fault zone and other similar areas.