塔北隆起中西部新近纪末构造应力场数值模拟

根据油田地震资料解释和构造分析,建立了新近纪末塔北隆起中西部平面与剖面地质模型,通过线弹性有限元方法的计算,得出该地区应力场模拟结果。构造应力场模拟结果表明,区域性南北向挤压应力控制了整个塔北隆起中西部新近纪末的构造应力场;研究区内牙哈断裂、轮台断裂、红旗断裂、英买7断裂在新近纪末为压扭性断裂,并具有左行走滑分量,喀拉玉尔滚断裂为右行走滑断裂,羊塔克断裂为纯压性逆冲构造;在区域挤压应力作用下,受主干断裂影响形成的局部构造应力场控制了局部次级构造类型的产生;从剖面应力场模拟结果来看,最大主应力方向在中央断隆区由水平变为倾斜,垂向应力分量变大,是导致压拱构造形成的主要因素。

Numercial Simulation of Tenconic Stress Field at the end of Neocene in the Midwest of Northern Tarim Basin

The plane and profile geological models at the end of Neocene in the midwest of Tabei uplift are established on the basis of seismic data of oil field and tectonic analysis. Using linear elastic finite element method, the results of numerical simulation of tectonic stress field of this area are gotten. Modeling results indicate that N-S regional compressive stress dominates the stress field of the whole area at that time, as well as that all faults of Yaha, Luntai, Hongqi, Yingmai 7 are compresso-shear structures with sinistral strike slip, while Kalayuergun fault is right lateral, and Yangtake fault is pure compressive thrust. In the condition of regional compressive stress, local stress field is formed, and affected by the main faults, which controlles the generation of secondary structures. In the modeling results of profile stress field, the orientation of the major principal stress change from horizon to incline in the middle of the uplifting area and the vertical stress component becomes bigger, which is the main factor to control the development of the compressional and subtuberant strutures.