库车坳陷新生代构造应力场恢复

库车坳陷的构造变形及演化与南天山造山带的发育密切相关。库车坳陷新近纪以来的喜马拉雅晚期构造运动最为强烈,形成了天山山前大型冲断带,并造就了现今的构造格局。通过对库车坳陷北部构造样式的识别及各种应力场指示标志的测量、统计和构造解析,对野外获得的应力场指示标志划分了期次,认为喜马拉雅晚期应力场标志为近南北向挤压。结合库车坳陷区域构造要素,如地质体几何形态、边界条件、岩石力学参数等,运用弹性力学有限元数值模拟的方法获得了喜马拉雅晚期库车坳陷的区域应力场。模拟结果表明,库车坳陷喜马拉雅晚期最大主压应力方向为近南北向,与古应力场标志拟合较高,可以为库车坳陷裂缝预测和评价提供依据,对勘探开发有应用价值。

An analysis of Cenozoic tectonic stress fields in the Kuqa depression

The structural deformation and evolution of Kuqa depression is closely related to the development of the South Tianshan Orogen. The late Himalayan period witnessed the most intense tectonic movement in this area, which resulted in a large thrust belt and created the present tectonic framework. By analyzing geological structure and geological settings, the authors differentiated the periods of the stress field indicators, and the indicators of the late Himalayan period show nearly NS-trending compression. The authors also simulated the stress field of the Kuqa depression during the late Himalayan period based on elastic mechanics finite-element method, in consideration of essential structural factors such as geometry of the basin, boundary conditions, and rock mechanics parameters. The result of the simulation indicates that the maximum principal compressive stress of Kuqa depression is in nearly north-south direction, which fits well with the stress field indicators. This result can be used as the basis for fracture prediction and evaluation and also has application value in exploration and development.