走滑断裂演化程度的表征参数研究

走滑断裂及其相关构造具有巨大的油气勘探价值，准确认识走滑断裂的演化程度关乎走滑构造带油气勘探的效果。前人的研究已经对走滑构造的生长演化过程有了定性认识，但仍缺乏客观定量确定走滑断裂带演化程度的依据，其核心问题是缺少能够表征走滑断裂演化程度的参数。为解决此问题，基于自身开展的里德尔剪切构造物理模拟实验，采集平面图像，进行了走滑断裂带内断裂几何学参数的统计分析。通过分析断裂带演化过程中平面结构阶段性变化与几何学统计参数变化的对应关系，揭示了断裂演化过程中几何学参数的变化规律，提出了将同一条断裂带内相邻断裂间夹角数据的标准差作为走滑构造演化程度表征参数的新认识。走滑断裂带演化程度与断裂带内相邻断裂夹角数据标准差具有明显相关关系，不同演化程度中的平面构造样式与断裂带内相邻断裂夹角数据的标准差值分布区间相对应；依据断裂平面组合样式，走滑断裂演化阶段可以划分为剪切单向破裂阶段、剪切雁列破裂阶段、剪切连通破裂阶段，分别对应断裂带内相邻断裂夹角数据标准差值(S)范围为1＜S＜4、4≤S＜8、S≥8；针对实际的走滑断裂带，通过统计断裂带内相邻断裂夹角数据的标准差能够分析出走滑断裂的演化程度。

Characterization parameters of the evolution degree of strike-slip faults

Strike-slip faults and their related structures have great value for oil and gas exploration. Accurate understanding of the evolution degree of strike-slip faults is crucial to oil and gas exploration in strike-slip structural belts. Previous studies have had a qualitative understanding of the growth and evolution process of strike-slip faults, but there is still a lack of objective and quantitative basis to determine the evolution degree of strike-slip fault zone. The key is the lack of parameters that can characterize the evolution degree of strike-slip faults. In order to solve this problem, this paper, based on the independent physical simulation experiment of Riedel shear structure, collected plane images and carried out a statistical analysis of fault geometry parameters in strike-slip fault zone. By analyzing the corresponding relationship between the periodic change of plane structure and the change of geometric statistical parameters during the evolution of fault zone, the change law of geometric parameters during the evolution of fault zone is revealed, and a new understanding is proposed that the standard deviation of the angle data between adjacent faults in the same fault zone is taken as the characterization parameter of the evolution degree of strike-slip faults. The main conclusions are as follows: (1) The evolution degree of strike-slip fault zone is significantly related with the standard deviation of the angle data between adjacent faults in fault zone, and the plane structural style in different evolution degrees corresponds to the distribution interval of the standard deviation of the angle data between adjacent faults in fault zone; (2) According to the combination pattern of fault planes, the evolution stage of strike slip fault can be divided into shear unidirectional fracture stage, shear en echelon fracture stage, and shear connected fracture stage, and the corresponding standard deviation (S) of the angle data between adjacent faults in fault zone is 1 < S < 4, 4≤S < 8, and S≥8, respectively; (3) For the actual strike-slip fault zone, the evolution degree of strike-slip faults can be revealed by statistical analysis of the standard deviation of the angle data between adjacent faults in fault zone.