Typical Salt Structural Styles And Numerical Simulations In Western Tabei Uplift,Tarim Basin

In the western part of Tabei uplift,thick gypsum salt rocks were developed,which was detachment,affected the tectonic deformation to form salt structures,and played an important role in oil and gas accumulation.In this paper,salt structures was explained based on drilling,well-logging and seismic data.The formation and evolution of salt structures were studied based on the combination of geological analyses with discrete element numerical simulations.The salt structures in this area are mainly detachment fold or salt core anticline in overburden and substrate.The salt structures were mainly formed during the Late Hercynian movement at the end of Permian with the closure of the southern Tianshan Ocean.In the early stage,the southward compression superposed by a left-handed wrench formed NW strike and left-lateral en echelon,and in the later stage,they were reformed by the magmatic intrusions to become locally NE strike.The salt structure was strengthened in Indosinian,Yanshanian and Himalayan periods.Based on the principle of similarity,discrete element numerical simulation models were designed,and the simulation results show that the typical salt structures in this area were developed in the slope background and were formed by southward compression with detachment folds in the overburden and pop-up structures in the substrate.Concerning the petroleum geology,the gypsum rock was the cap layer of the lower Cambrian.It controlled the deformation in the overburden and affected the deformation in the substrate.These deformations provided traps for oil and gas accumulation.