Seismic Inversion using full wavefied data XiaoLiang Duan1*, Yibo Wang2, Huizhu Yang1 1Department of Engineering mechanics, Tsinghua University, 100084, China 2Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, China *Corresponding author: gfkjdxdxl@yahoo.com.cn ABSTRACT Most seismic migration methods stress primary reflection data, it means that multiples is considered as noise and need to be removed prior to migration process. In fact multiples contain important medium property information which can be utilized to improve the quality of image. By introducing a background model, the difference between the known background properties and unknown real medium properties is inverted. Each gridpoint act as a scatterer in the background media. In our work, Finite-difference contrast source inversion method will be applied in seismic inversion with full wavefield data including surface-related and internal multiples, without including explicit computation of forward problem at each iteration step, this method can employ an inhomogeneous background medium. By solving an optimization problem to reconstruct the contrast function χ, which is a quantity having some connection with the real velocity distribution in the medium. Result of the process is an accurate angle-dependent reflectivity image as well as angle-dependent velocity model in subsurface. Key words: migration, inversion, anisotropy, multiple, scatter 1. INTRODUCTION Generally speaking, there are two possible approaches for velocity estimation from surface recorded seismic data, the two methods differ from the domain in which the information is used to update the velocity model. The first approach is formulated in the data space prior to migration, and it involves matching of recorded and simulated data using an approximate velocity model. The second approach is formulated in the image space after migration, in which it involves measuring and correcting image features that indicate model properties inaccuracies. Nowadays, migration and inversion have been two different approaches to reveal the subsurface information [4,6,9-11], Their fundamental theory is very different. But we can treat migration and inversion as a same form in mathematics. Although they have different physical meaning. So we can incorporate migration and inversion process together to analyze the seismic data[1]. One of the well-known full nonlinear inversion methods based on the integral equation(IE) formulation is the contrast source inversion (CSI) method[7,8]. The main
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