走滑断裂带贯穿过程与发育模式的物理模拟  

Analogue modeling of through-going process and development pattern of strike-slip fault zone

作　　者：肖阳[1] 邬光辉[1] 雷永良[2] 陈婷婷[1] 

机构地区：[1]中山大学广东省海洋资源与近岸工程重点实验室,广州510006 [2]中国石油勘探开发研究院,北京100083

出　　处：《石油勘探与开发》2017年第3期340-348,共9页Petroleum Exploration and Development

基　　金：国家自然科学基金(41472103)

摘　　要：结合实际地质资料设计9组砂箱模拟实验,并利用断层CT扫描技术研究简单剪切走滑带演化规律与发育机制。结果表明,R(Riedel)剪切断裂形成早、数量多,并有一组与主走滑带低角度相交,P剪切断裂(与R剪切断裂对称分布的压剪破裂)与Y剪切断裂(与主位移带近平行的剪切破裂)形成滞后,并在Y剪切断裂发育后才从分段构造连接成贯穿的走滑带。走滑带贯穿连通过程可划分为4个阶段:萌芽阶段、R剪切断裂发育阶段、P剪切与Y剪切断裂发育阶段、走滑带贯穿阶段。实验揭示了走滑断裂由基底向盖层递进传播的发育过程,萌芽阶段剖面上断裂逐渐向上散开发育,R剪切断裂发育阶段平面上向外散开后逐渐向主位移带收敛。雁列构造具有"螺旋-拖曳"发育模式,雁列断裂的长度增长速度呈约2倍于深度增长速度线性增长,而与主位移带夹角随深度呈二次函数变小。分析表明,最大主应力方向、盖层厚度是导致雁列构造"螺旋-拖曳"结构差异的主控因素。走滑断裂的物理模拟为塔里木盆地海相碳酸盐岩断裂解析与分层、分段的勘探开发实践提供了模型基础。Nine sets of sand-box experiments were designed according to actual geologic data to investigate the evolution pattern and development mechanism of simple shear strike-slip fault zone using the fault CT scanning technique. The experiment results show that R （Riedel） shear faults were developed early and more in number, and one set of these faults intersect with the principle displacement zone （PDZ） at lower angle; the P shear faults （being in symmetrical distribution with the R shear faults） and Y shear faults （subparallel to PDZ） were developed later than the R shear faults, and the fault zone was through-going only after the formation of Y shear faults. The through-going process of strike-slip fault zone can be divided into four stages： embryonic stage, R （Riedel） shear fault development stage, P shear fault and Y shear fault development stage, and through-going stage of fault zone. In the process, the faults developed progressively from the basement to the top cover, the faults spread upward in the profile at embryonic stage, and spread outward at first and then converged toward the PDZ on the plane at R shear faults development stage. The modeling demonstrates that the en echelon structure developed in ＂helicoidally drag＂ pattern, the length of the en echelon fault grew linearly at two times the growth rate of its depth, and the fault intersection angle with the PDZ decreased in quadratic function with the increase of its depth. The analysis reveals that cover thickness and the maximum principal stress direction are the main factors causing the difference in ＂helicoidally drag＂ structure. The modeling provides guidance for the strike-slip fault interpretation and evolution study, and for layering and segmentation of faults in the marine carbonates of the Tarim Basin.

关 键 词：走滑断裂带 构造物理模拟 构造演化 雁列构造 “螺旋-拖拽”模式 塔里木盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]