基于方位—反射角度道集的高斯束层析速度建模方法及实现  

Method and application of Gaussian beam velocity tomography based on azimuth-reflection angle domain common imaging gathers

作　　者：蔡杰雄[1] CAI Jie-Xiong(SINOPEC Geophysical Research Institute,Nanjing 211103,China)

机构地区：[1]中国石油化工股份有限公司石油物探技术研究院,江苏南京211103

出　　处：《物探与化探》2018年第5期977-989,共13页Geophysical and Geochemical Exploration

基　　金：国家科技重大专项(2016ZX05014-001-002)

摘　　要：层析反演是速度建模中最重要的方法之一,结合偏移成像在成像域进行波动方程线性化走时层析速度建模是当前比较实用有效且精度较高的技术组合。文中首先给出了高斯束偏移提取方位—反射角度道集的方法,之后从高斯束偏移角度道集出发,在波动方程的一阶Born近似和Rytov近似下,推导了成像域波动方程线性化走时层析方程及其显式表达的层析核函数,并利用高斯束传播算子计算该核函数。基于高斯束传播算子的偏移成像与层析成像相结合进行深度域速度建模迭代及偏移成像,体现了速度建模与成像一体化的思想。数值计算及实际数据应用证明了基于高斯束传播算子的层析成像与偏移成像方法的有效性。Tomography is one of the most important velocity building methods. Travel time tomography in image domain,implemented with migration,is widely used in velocity model building currently.The authors first introduced the method to output the azimuth-reflection angle gathers,and then,under the assumption of the first-order Born and Rytov approximation of wave equation,started with the imaging condition of Gaussian Beam Migration to derive the linear relation between traveltime perturbation and velocity perturbation in the image domain,with which the authors constructed the explicit expression of kernel function for the wave equation traveltime tomography and established the traveltime tomography equation.The key to computing the kernel is how to compute the Green function in the background model.Making use of the Gaussian beam propagation operator to compute the kernel function can be flexible and efficient.Together with the implementation of Gaussian beam propagation operator in migration,the authors truly realized the integrated technological process of velocity building and migration. Numerical tests and field data application demonstrate that the Gaussian-beam-propagator based traveltime tomography in image domain is effective.

关 键 词：高斯束 走时层析 核函数 偏移成像 角度道集 

分 类 号：P631.4[天文地球—地质矿产勘探]