Target-oriented wave-equation least-squares migration/inversion with phase-encoded Hessian

摘要: Prestack depth migration produces blurred images resulting from limited acquisition apertures, complexities in the velocity model, and band-limited characteristics of seismic waves. This distortion can be partially corrected using model-space least-squares migration/inversion approach, where a target-oriented wave-equation Hessian operator is computed explicitly then inverse filtering applied iteratively to deblur or invert for reflectivity. However, one difficulty cost computing explicit operator, which requires storing large number Green's functions, making it challenging large-scale applications. A new method compute wave-equation-based problem modifies original formula, enabling efficient computation this operator. An advantage that eliminates disk storage functions. The modifications, however, also introduce undesired crosstalk artifacts. Two different phase-encoding schemes, plane-wave-phase encoding random-phase encoding, suppress crosstalk. When randomly phase-encoded Sigsbee2A synthetic data set, an improved subsalt image with more balanced amplitudes obtained.