【摘要】 弹性波高斯束偏移是一种兼顾成像精度与计算效率的多分量地震成像方法,但当前的研究多集中在各向同性介质声波、弹性波成像和各向异性介质声波成像,针对各向异性介质弹性波偏移的文献相对较少。为此,在前人的研究基础上,发展了各向异性介质弹性波射线追踪方程,以二维各向异性弹性波Kirchhoff-Helmholtz积分为基础,利用弹性动力学表征的格林张量推导了各向异性介质中弹性波波场正、反向延拓公式,提出了一种针对各向异性介质多分量地震数据的成像方法。通过在成像公式中引入权函数,很好地压制各向异性介质成像中不同波型引起的串扰。通过引入符号函数,解决了转换波成像过程中的极性反转问题。TTI介质洼陷模型和TTI介质多层构造模型试算结果表明:与各向同性介质弹性波高斯束偏移方法相比,各向异性介质弹性波高斯束偏移成像结果的信噪比较高、同相轴连续性较好、构造位置更准确;使用多分量地震记录,利用纵、横波波场信息成像,有效提高了成像分辨率;与传统的基于标量波场的成像方法相比,所提方法的适应性更好。更多还原

【Abstract】 Elastic wave Gaussian beam migration is a multicomponent seismic imaging method with higher imaging accuracy and computational efficiency.By now more researches have focused on acoustic and elastic imaging of isotropic media and acoustic imaging of anisotropic media,but less on elastic wave migration of anisotropic media.This paper proposes the ray tracing equation of elastic wave in anisotropic media,derives the forward and backward continuation formulas of the elastic wave field in anisotropic media based on the Kirchhoff-Helmholtz integration of 2 Danisotropic elastic wave and using the Green tensor characterized by elastic dynamics,and establishes an elastic Gaussian beam migration method for multicomponent seismic data of anisotropic media.In addition,the weight function is introduced into the imaging formula to suppress the crosstalk caused by different waveforms;and the sign function is introduced to facilitate the polarity inversion during converted wave imaging.Applications on a TTI sag model and a TTI multilayer model show that the imaging results of anisotropic elastic Gaussian beam migration have higher SNR,more continuous seismic events,and more accurate structural position than the similar isotropic migration.With multicomponent seismic data,and information of P-wave and S-wave fields,the method provides the imaging result with higher resolution.Moreover,it has better adaptability than the conventional imaging method based on scalar wave field.更多还原