【作者】 全红娟；

【导师】 朱光明；

【作者基本信息】 长安大学 ， 地球探测与信息技术， 2015， 博士

【摘要】 随着油气矿产资源勘探和开发的发展,裂缝性油气藏研究已成为一个非常重要的勘探领域。裂缝性油气藏具有储层规模小,非均质和各向异性效应都很强的特点。要进行裂缝性油气藏的勘探开发,首先需要研究地震波在裂缝性地层中的传播特征,才能更合理地分析和解释实际资料。因此,本文针对如何分析地震波在裂缝介质中的传播特征展开了相关的系列研究工作。论文详细地讨论了裂缝介质中地震波交错网格高阶有限差分的数值模拟方法,分析了地震波震源数值模拟的加载方式及波场特征,并从横波分裂、速度各向异性、方位AVO等三方面入手研究了地震波在裂缝介质中的传播特征。取得的主要研究成果如下：1.研究了裂缝介质地震波场的交错网格高阶有限差分模拟方法。详细地给出了三维和二维三分量波动方程数值模拟中的PML吸收边界和MPML吸收边界；完善了地震波场的交错网格高阶有限差分模拟方法,补充修改了相关的软件,将二维三分量和三维数值模拟发展为观测系统、震源加载灵活的波动方程数值模拟；提出了一种介质对称轴和观测坐标轴互换的方法,使二维三分量观测结果近似代替三维观测结果,既避免了大量的三维数据运算,又能有效地研究裂缝介质的横波分裂现象。这项成果对实际观测有重要的实用价值。2.给出了震源加载方式与激发的波场特征的关系,并从物理上进行了分析。得出：压力源加载在正应力项才能得到单纯的P波源；剪切力源加载在所有切应力项才能得到单纯的S波源；(水平、横向、垂直)集中力源加载在(x方向、y方向、z方向)体力项才能得到既有P波又有S波的方向力源。这项成果在实际应用中有指导意义。3.详细研究了裂缝介质中地震波的横波分裂机理及波场特征,明确了SV波、SH波与S1波、S2波间的关系。以具体模型为例,给出横波分裂中的可观测量与震源类型、方位角、传播介质、介质分界面和观测系统之间的关系。特别研究了横波分裂后快慢横波的时差、振幅和能量随方位角的变化规律。这一成果有重要的应用价值。4.研究了裂缝介质中地震波的速度各向异性及方位AVO效应。提出各向异性参数与裂缝介质中波的相速度、群速度及PP波反射系数间的关系。更多还原

【Abstract】 With the developments of detecting technologies of oil-gas mineral resources exploration, the research of fractured oil-gas reservoir has become an important exploration field. Fractured oil-gas reservoirs are of small scales with highly heterogeneities and anisotropies. To carry out the exploration of fractured reservoirs, one need study the propagation of seismic wave in crack media first, which can help us to analyze and interpret the actual data more reasonably. Therefore, this paper focuses on the studies of the method of analyzing the propagations of seismic waves in crack media.This paper discussed the crack wave staggered grid high-order finite difference numerical simulation method, analyzed source loadings and wave field properties in numerical simulations, and studied the behaviors of seismic wave propagation in fractured medium through velocity anisotropies, shear wave splitting and range AVO. The main results are summarized as follows:1. It researches the Simulation method of high order staggered-grid finite difference in crack media, we respectively derived the PML and MPML absorbing boundary condition in 3D and 2D3C simulation. The seismic wave field high-order staggered-grid finite difference simulation method is improved, the relevant software is amended and supplemented, the 2D 3C and 3D numerical simulation are also developed to be suitable for any observable system and flexible loading sources. A new interchange way of symmetry axis and observation axis in media is proposed, which leads to the observation results can take the place of 3D observations, avoids a large number of 3D data operation, and can effectively study the S-wave splitting phenomenon in crack media.2. It not proposes relations of the loading modes of seismic sources and wave field prperties but also analyses physics mechanism. The conclusion is that:to get pure P wave sources, the pressure sources should be loaded on the normal stress terms; to get pure S wave sources, shear force source should be loaded on shear stress terms; and (horizontal, vertical, horizontal) concentrated force sources should be loaded on (along x, y, z direction) volume force terms to can get both P wave and S wave source directions. The result has guiding significance in actual application.3. It researches the mechanism of S-wave splitting and wave field characteristics in crack media in detail, media, and analyzed the correspondences between SV, SH waves and S1, S2 waves. Based on the concrete models, the paper provides the influencing factors of S-wave splitting ranging over source type, azimuth, medium, interface and observation system, et al.In particular, we studied the time differences, and the variations of amplitude and energy in terms of azimuth angle between fast and slow waves after the shear wave splitting. And, the conclusion turns out to be that, the time difference between the fast and slow waves increases with the azimuth angle, and the amplitudes of fast and slow wave components will change according to certain rules, and the energy in fast and slow waves will be redistributed. The result provides the important application value.4. It analyses the velocity anisotropy and azimuth AVO in crack media, gives the influences of anisotropic parameters on phase velocity, group velocity and PP wave reflection coefficients in crack media are summarized.更多还原