The invention provides a mixed domain Fourier finite difference
prestack depth migration imaging method based on the
coefficient optimization in order to improve the earthquake migration imaging accuracy of a complex high steep structure region and forcefully guide accurate prediction and exploitation of oil-gas resources. According to the method,
wave field extrapolation operators are expanded through a pade approximation rational function, expanded coefficients are optimized through a Chebyshev polynomial, new
wave field extrapolation operators are obtained trough deduction, relative errors between the new
wave field extrapolation operators and
wave equation accurate wave field extrapolation operators are reduced, the approach degree of the wave field extrapolation operators is increased, and the earthquake migration imaging accuracy of the complex high steep structure region is improved while computational efficiency is guaranteed. The imaging effect of the improved mixed domain Fourier finite difference migration method on the Marmousi
model migration section is compared with that of a conventional Fourier finite difference migration method on the Marmousi
model migration section, and it is proved that the mixed domain Fourier finite difference
prestack depth migration imaging method obtained based on
coefficient optimization has higher migration imaging accuracy. The method has important significance in improving the earthquake migration imaging accuracy of the complex high steep structure region.