The Study Of Wave Equation Depth Migration With Optimum Fourier Finite-Difference Method

With the development of economic, energy security issues have becomeincreasingly prominent.The supply of oil and gas can’t fulfil the needs of the society.At the same time, more and more difficult in oil and gas exploration.For seismicexploration,the imaging accuracy and computational efficiency are the problems thatneed to be solve now. Based on wave equation depth migration method is an effectiveway to solve the problem of complex geology imaging when the lateral velocitychanges strongly. In this paper, the Fourier finite-difference (FFD) depth migrationmethod based on wave equation are studied theoretically, and the parameters of theFFD are optimized by using simulated annealing alrigothm.Main contens as follows:First part shows the background of seismic exploration, the development andhistory of the seismic migration. Focus on wave quation migration: the principle ofseismic migration, the theory of wave equation and the principle of wave equationmigration.at last, introduce the theoretical basis and alrigothm implementation aboutthe Split-step Fourier (SSF) method and Fourier finite-difference method.Second part focus on the non-linear optimization method-simulated annealing(SA) alrigothm: the essential principle, implement process and parameters control.Optimized the parameters by using SA alrigothm and improved the image accuracy ofwider angles without additional computational cost.Finally, used the test of migration pluse response and SGE/EAGE salt model, itis found that Optimum Fourier finite-difference (OFFD) method resolves the widerangles and the imaging more accurately than the FFD method and the SSF method.