CONCLUSION

I have developed a poststack and a prestack datuming scheme that use wavefield depth extrapolation. The method allows the use of any depth extrapolation technique such as phase-shift, split-step, or finite-difference extrapolation. The derivation of the datuming algorithms is obtained by transposing and taking the complex conjugate of the corresponding forward modeling operator which does upward extrapolation from a flat surface to an irregular surface. The exact conjugate relation between the forward modeling operator and the datuming operator is demonstrated algebraically and confirmed by the dot-product test. Several tests of the datuming algorithms with synthetic data and real data show that the method works well.