Simultaneous pre-stack prediction of lithology, geofluids, and physical properties in deep tight sandstone reservoirs based on recharacterization of reflection coefficient approximation equation and Bayesian inversion strategy

Pre-stack seismic inversion is an important tool for the quantitative interpretation of complex reservoirs. However, the increasing demands of deep tight sandstone exploration require a more integrated characterization of lithology, physical properties, and geofluid. Current inversion methodologies often treat these reservoir parameters separately, leading to fragmented understanding and redundant workflows. This study proposes a novel pre-stack seismic inversion method that simultaneously estimates lithology and physical properties of deep tight sandstone reservoirs. Its core innovation lies in establishing a direct, rock-physics-based link between seismic response and multiple reservoir attributes. The specific process involves: (1) Conducting a comprehensive rock-physics analysis to identify parameters sensitive to lithology, permeability, and geofluid types; (2) Deriving a novel reflection coefficient approximation through parameter combinations and mathematical simplification, followed by accuracy verification and feasibility assessment for seismic inversion; and (3) Implementing a model-constrained iterative reweighting Bayesian inversion scheme to reliably estimate model parameters. The effectiveness and reliability of the method have been validated through model tests and field data applications. This approach enables the identification of favorable zones within tight sandstone reservoirs, offering a feasible and efficient solution for their integrated seismic interpretation.