Tectonic characteristics and hydrocarbon accumulation in the eastern section of Maigaiti slope, Tarim Basin

Based on fault-related fold theory and the latest 3D seismic data, the tectonic deformation characteristics in the Yubei area on the eastern Maigaiti slope in the Tarim Basin were analyzed through seismic interpretation, and the relationship between tectonic characteristics and hydrocarbon accumulation was discussed. The study area featured vertically layered deformations. The pre-Cambrian basement developed normal faults and formed fault blocks. The Paleozoic developed slip-thrust faults along the Middle and Lower Cambrian gypsum rocks with a uniform slip surface, and the faults and folds were segmented horizontally. There are asymmetric (trishear) and symmetric (fan) folds in the Upper Paleozoic of the hanging wall, associated with fold-related fractures. Cenozoic did not develop faults or folds, and was represented by a west-tilting slope. Faults, tectonic fractures and unconformities constituted vertical and horizontal carrier systems for hydrocarbon migration in the Upper Paleozoic. The Upper Paleozoic kink bands extended reservoir space, and the associated structural fractures effectively improved reservoir performance. Influenced by the Late Hercynian and Himalayan tectonic movements, the intra-Ordovician karst reservoirs and the Upper Paleozoic fractured reservoirs are favorable accumulations of oil and gas.