Abstract

In prestack seismic inversion for structurally complex areas, elastic parameters commonly show strong directional heterogeneity (layer-parallel continuity versus cross-layer discontinuities), so conventional structure-guided schemes based on isotropic regularization often struggle to achieve both numerical stability and sharp interface resolution. To address this issue, we develop a structure-oriented, direction-decomposed Lp-L2 regularization method for prestack multi-trace joint inversion of P-wave velocity (Vp), S-wave velocity (Vs), and density (ρ). Dip information extracted from poststack seismic data is used to construct a dip-guided directional operator that locally projects the Cartesian model-gradient field onto the tangential and normal directions of the structural field, corresponding to along-layer and cross-layer components, respectively. Different priors are then imposed: L2 smoothing along layers enhances lateral continuity and stabilizes the inversion, whereas a nonconvex Lp sparsity constraint across layers concentrates updates at a limited number of geological discontinuities and preserves sharp contrasts at faults and bed boundaries, thereby mitigating the over-smoothing typical of dip-guided L2 inversion. The resulting formulation is embedded in a linearized prestack Amplitude Versus Offset (AVO) framework and solved efficiently using the Alternating Direction Method of Multipliers (ADMM) algorithm. Synthetic tests and field-data applications demonstrate improved delineation of faults and thin-bed boundaries under noise, with reduced errors and higher correlation relative to a classical structure-guided L2 approach. These results indicate that the proposed method provides a practical and effective route for high-resolution prestack elastic-parameter characterization in complex tectonic settings.

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