断层应力封闭性的FLAC模拟研究

断层带及其旁侧应力性质是决定断层封闭性的重要因素, 采用FLAC-2D有限差分计算机程序, 模拟了断层带应力分布及其随深度变化。在梯形水平应力和垂直载荷条件下, 断层封闭性具有垂向分段特征: 浅部断层带处于应力松弛或张应力状态, 断层带相对开启, 对地质流体不具封闭作用; 深部断层带处于压应力集中状态, 断层具有良好的封闭性; 二者之间为过渡段。断层带应力封闭性模式得到声波时差资料的印证。 

Application of FLAC in simulation of fault stress seal

The stress property within and near a fault is an important factor of controlling fault seal. In this paper the FLAC-2D finity difference program is used to simulate stress distribution in fault zone and stress variety with depth quantitatively. The results of the calculating simulation show that under the condition of trapezoid horizontal stress and vertical load, the fault seal character could be classified into three sections after depth: in shallow section fault zone is in stress relaxation and open to geological liquids, fault zone is in stress concentration and well sealed in deep section, and a transition section exists between the above two sections. The stress seal model of fault has been supported by data of the sound wave time-difference from oilfield.