Abstract:

The Kuqa depression is controlled by several sets of detachment layers, and the structural deformation of the fault belt is complicated. Clarifying the main controlling factors of complex structural deformation in structure belts and their formation and evolution processes is of great significance for understanding the genetic mechanisms of foreland thrust belt structural deformation controlled by detachment faults and for oil and gas exploration. In this paper, four sets of numerical simulation experiments are designed and completed by applying discrete element numerical software, conducting simulation analysis on key factors such as structure paleomorphology, detachment layer, and strata denudation to explore their impact on the complex structural deformation of foreland thrust belts. The simulation results show that: The distance of a structure belt to an early paleo-uplift affects the development of the sub-salt structural morphology. As the distance to the paleo-uplift decreases, it becomes easier to produce wider and continuous anticline morphology. The friction coefficient of the sub-salt detachment layer affects the distance of stress propagation and the differences in the morphology of structures above the salt. The larger the friction coefficient is, the smaller the displacement of the forward propagation of the stress, and the more significant the differences in the structural deformation morphology above the salt. Meanwhile, strata denudation affects the stress produced by the sub-salt compaction, thus increasing the size of the sub-salt structure.

Key words: Kuqa depression, structucal deformation, detachment layer, numerical simulation, stress and strain