Surface model correction by wave-field continuation
Li Luming, Luo Shengxian
State Key Laboratory for Reservoir Geology and Development Engineering, Chengdu Science and Engineering College, Chengdu City, Sichuan Province 610059, China
Abstract：In order to solve the problem of influence of complicated surface velocity change on reflection wave,on the basis of tomographic inversion of first break surface model,the paper studied theory and method for surface model correction by wave-field continuation,and formed a suit of effective calculation method.Its basic principles are:P-wave displacement equation in frequency-time domain is transformed a basic wave continuation equation by split method,then dispersion and absorption boundary condition is carried out and wave continuation value is obtained by using high-order finite-difference;in a condition of lateral constant velocity for wave continuation,it carried out by using phase-shift method to solve single-squareroot equation in a frequency-wavenumber domain.The concrete practices are:①continuation of receiver point on the gather to top of high-velocity bed;②continuation of shot point to top of high-velocity bed;③separate continuation of receiver point and shot point to datum of CMP position by replaced velocity;.carrying out velocity analysis,NMO correction and stack
