渤海湾盆地临南洼陷张扭构造演化及应力场数值模拟

THE EVOLUTION OF TRANSTENTIONAL STRUCTURE AND NUMERICAL MODELING OF STRESS FIELD,LINNAN SUBSAG,BOHAI BAY BASIN

为了考察渤海湾盆地临南洼陷张扭构造的发育特征和成因机制,在解释30余条三维地震剖面的基础上,估算及分析伸展率在时间和空间上的变化规律,绘制了Es3—Es1、Ed和Ng—Nm3个时期的断层平面展布图,利用FEPG有限元软件,建立二维线弹性数值模型,模拟了3个时期的构造应力场。结果表明,临南洼陷的最大主应力和最大剪应力,在平面上都是东北部大、西南部小;从Es3时期到Nm时期,最大主应力和最大剪应力都是逐渐减小的,数值模型边界上的剪应力分量均大于张应力分量,而且剪应力分量与张应力分量的比值是逐渐增加的。通过研究,将临南洼陷张扭构造发育的力学机制量化,并为郯庐断裂和兰聊断裂在惠民凹陷乃至渤海湾盆地的作用时间、方式的研究提供参考。

To investigate characteristics and formation mechanism of transtentional structures developed in Linnan subsag of the Bohai Bay basin,more than 30 3-D seismic sections have been interpreted,temporal and spatial distributions of extension rates have been estimated and analyzed,and the planar distribution of faults in three stages,Es3-Es1,Ed and Ng-Nm,have been plotted.2-D linear elastic numerical models have been established to simulate the stress field of the above mentioned three stages,using finite elemen...