论文详情
地层的粘弹性对地震波产生的吸收和衰减规律非常复杂,所以研究地震波在粘弹性介质中的传播规律对地震勘探有着重要的意义。近似解析离散化方法是近年来出现的一种有限差分数值模拟方法,籍此探讨了几种近似解析离散化方法的原理和过程。通过与一维粘弹声波方程解析解的对比,认为改进的近似解析离散化方法(INAD)的精度、稳定性和计算效率更具优势,并将其首次应用于二维粘弹声波方程数值模拟。通过数值模拟,重点分析了声波振幅、频率、频带宽度随品质因子及传播距离的衰减规律,粘弹介质中的地震波不仅因波前扩散导致振幅衰减,还因吸收作用导致振幅和频率同时衰减,利用其衰减特征可以指导含油气储层的预测。
Viscoelasticity of the media has a very complicated relationship with the absorption and attenuation of seismic wave energy.Therefore,the research on the propagation law of seismic waves in the stratigraphic equivalent media carries great significance to the seismic exploration.Nearly-analytic discrete method is a finite-difference numerical simulation method developed in recent years.In this paper,the author firstly explored the principles and process of four different nearly-analytic discrete methods.In comparison with the one-dimensional analytical solutions,the improved nearly-analytic discrete method (INAD) was proved to excel in precision,stability and computational efficiency.Then INAD was applied to the numerical simulation of 2D viscoelastic acoustic wave equation for the first time.With the simulated viscoelastic wave field,the author focused on analyzing the propagation law of the amplitude,frequency and bandwidth of the acoustic wave with the change of Q values and propagation distance The amplitude of the seismic wave in the viscoelastic medium reduces not only due to the wavefront diffusion,but also the absorption which attenuates the frequency at the same time. These attenuation characteristics can guide the prediction of the oil and gas reservoir.The amplitude of the seismic wave in the viscoelastic medium reduces not only due to the wavefront diffusion,but also the absorption which attenuates the frequency at the same time.These attenuation characteristics can guide the prediction of the oil and gas reservoir.
Keywords: viscoelastic media,nearly-analytic discrete method,numerical simulation,Q value,absorption and attenuation
国家重点基础研究发展计划(973计划)(2013CB228605)和中国石油科技创新基金项目(2015D-5006-0301)联合资助。