磨溪—高石梯区块断层对裂缝分布的控制作用

Fault System and Its Controlling Effect on Fracture Distribution in Moxi–Gaoshiti Block, Sichuan Basin, China

为了查明磨溪—高石梯区块断层展布与裂缝分布特征,以地质力学理论为指导,利用地震、测录井、岩芯及相关实验测试资料,识别不同断层类型,划分断层级别,开展裂缝定量预测工作,建立断层与裂缝分布关系模式。结果表明,磨溪—高石梯区块断层在纵向上规模大,延伸长,断开层位多,具有明显的分层性,可划分为3个构造层,且在平面上具有显著的分区性和分带性。不同规模、走向及性质的断层对裂缝的分布影响显著,裂缝密度普遍在1.5～5.0条/m,最高为7.0条/m,高值区主要分布于断层及其周缘。裂缝开度在断层发育带最高可达3 mm。磨溪—高石梯区块是一套断层-裂缝共生系统,主断裂控制次级断裂及裂缝的发育,次级断层控制局部裂缝发育。

In order to determine the fault and fracture distribution characteristics of the Moxi–Gaoshiti block,faults were classified into different types and levels based on geomechanical theory and seismic,logging,core,and relevant experimental data.Fractures were quantitatively predicted,and the relationship between the distributions of faults and fractures was established.The results showed that the faults in the Moxi–Gaoshiti block have a large scale in the vertical direction,long extensions,a large number of disconnected layers,and obvious delamination.They can be divided into 3 structural layers,and have significant plane partitioning and banding.Faults with different scales,directions,and characteristics have significant influences on fracture distribution.Fracture density is generally 1.5~5.0/m with a maximum of 7.0/m.Zones with high values are primarily distributed in the fault and its periphery.The maximum fracture opening in the fault development zone can reach 3 mm.The Moxi–Gaoshiti block is a fault-fracture symbiotic system.The primary fault controls the development of secondary faults and fractures,and the secondary fault controls the development of local fractures.