叠合盆地内部小尺度走滑断裂幕式活动特征及期次判别——以塔里木盆地顺北地区为例

Multi-stage activity characteristics of small-scale strike-slip faults in superimposed basin and its identification method: a case study of Shunbei area, Tarim Basin

黄诚

HUANG Cheng

中国石油化工股份有限公司 西北油田分公司, 乌鲁木齐 830011

SINOPEC Northwest Oilfield Branch Company, Urumqi, Xinjiang 830011, China

叠合盆地内部走滑断裂一般具有多期活动特征，其幕式形成演化过程与叠合盆地形成演化的重要构造变革期匹配。一般情况下，走滑断裂带在不同构造时期的会聚（或拉伸）应力场中，会在同期近地表构造层形成特有的伴生构造样式，最终构成一个完整的垂向构造序列。如果将各构造层特有的走滑伴生构造作为同期走滑断裂活动的地质记录，即可从现今地下地质结构中逐期恢复走滑断裂幕式活动过程，进而判定断裂活动期次。此外，在走滑断裂幕式滑移过程中，常会出现水平滑移方向改变和错断构造-沉积地质体的现象。这2种现象实际上体现了走滑断裂运动学特征的核心内容，即滑移方向和滑移距离，也可作为走滑断裂活动期次判定的重要依据。基于盆地构造-沉积演化背景研究，将塔里木叠合盆地划分为5个构造层，厘定走滑断裂体系的垂向构造序列及主要伴生构造样式。通过对塔里木叠合盆地不同构造层走滑伴生构造的几何学和运动学特征解析，形成了基于地震资料判别断裂活动期次的2类7种适用性技术方法。

The strike-slip faults in superimposed basins usually experienced multi-stage activities. The episodic formation and evolution of strike-slip faults match with the important tectonic transformation periods of superimposed basins. Generally speaking, strike-slip fault zones converge (or stretch) in stress fields at different tectonic stages. It will result in the formation of specific associated structural styles of near-surface tectonic layers in the same period. Finally, a complete vertical tectonic sequence is formed. If the strike-slip associated structures peculiar to each tectonic layer are taken as geological records of strike-slip fault activities in the same period, the episodic activity of the strike-slip faults can be restored step by step from the present underground geological structure, and then the active periods of faults can be determined. In addition, during the episodic slip of strike-slip faults, changes in horizontal slip direction and faulted tectonic-sedimentary geological bodies often occur. These two phenomena actually reflect the core content of the kinematic characteristics of strike-slip faults, namely, the direction and distance of slip. It can also be used as an important basis for judging the active stages of strike-slip faults. Therefore, the Tarim superimposed basin is divided into five tectonic layers on the basis of the study of basin tectonic-sedimentary evolution background. On this basis, the vertical structural sequence and main associated structural styles of strike-slip fault system in the study area are determined. The geometric and kinematic characteristics of strike-slip associated structures in different tectonic layers of Tarim superimposed basin are analyzed. Two types with seven applicability techniques for distinguishing active periods of faults based on seismic data have been formed.

国家科技重大专项“塔里木-鄂尔多斯盆地海相碳酸盐岩层系大中型油气田形成规律与勘探评价”（2017ZX05005-002）资助。

https://doi.org/10.11781/sysydz201903379