Stratigraphic forward modeling (SFM) is a numerical approach used to reconstruct sedimentary basin evolution by simulating the infilling and tectonic evolution process of strata. The challenge is that existing approaches inevitably require trade-offs among modeling fidelity and computational cost. We present a novel clastic stratigraphic forward modeling (CSFM) approach to reducing computational cost while retaining key flow and transport behaviors relevant to stratigraphic architecture. In CSFM, Lagrangian water particles affect momentum and sediment, while a fixed Eulerian grid stores topographic elevation and lithologic fractions. A simplified form of the Navier–Stokes equations is proposed to compute the trajectories of fluid particles, which can greatly reduce the computational cost. Sediment dynamics are represented by coupled suspended load and bedload modules. To validate CSFM, we constructed a synthetic alluvial fan model and performed stratigraphic forward modeling on it. Five lake-level cycles were imposed and results showed that cyclic sand–clay couplets and isolated channel sand bodies were formed during repeated progradation and backstepping. These results are consistent with established sedimentological knowledge, confirming the geological plausibility of CSFM.

Rock physics model provides an essential theoretical tool to quantify the impacts of reservoir physical parameters (porosity, water saturation, etc.) on seismic elastic properties including P- wave velocity and S-wave velocity. As a core module for deriving physical properties through joint well-seismic inversion, rock physics modeling accuracy directly determines the reliability of reservoir property prediction. Simultaneous characterization of pores and oriented fractures is required to refine modeling precision, yet the resulting excessive model parameters severely limit applications to field seismic data. To address the critical issue of applying pore and fracture anisotropic rock physics models to azimuthal seismic interpretation, this work decouples pores and oriented fractures during modeling. We postulate that pore variations control the model’s isotropic elastic properties, whereas oriented fracture characteristics dominate anisotropic parameters. Well-log data are utilized to invert key modeling parameters (matrix mineral elastic moduli, fracture porosity, etc.) for model correction. The corrected rock physics model is further coupled with the Rüger reflectivity equation to analyze how porosity and fracture azimuth alter seismic reflection coefficients and synthetic seismic records. The presented anisotropic rock physics correction method via parameter inversion greatly elevates modeling accuracy. Rock-physics-based analysis of azimuthal seismic reflection shows promising prospects for widespread use in fractured reservoir characterization.

This study investigates the combined effects of partial saturation and aligned fractures on P- and S-wave velocities and anisotropy in tight sandstones. Ultrasonic measurements (0.5 MHz) were conducted on three synthetic samples with a matrix porosity of 11.7% ± 1.2% and controlled fracture densities (0%, 3.12%, and 6.24%) under a full range of water saturation rate (S_w), from dry to fully water-saturated. Experimental results reveal that for fractured samples, the P-wave anisotropy parameter ε increases sharply as S_w decreases from 100% to approximately 60%, followed by a gentler variation at lower saturation. In contrast, fracture-induced shear-wave splitting (SWS) is predominantly governed by fracture density and exhibits weak dependence on S_w. To interpret these observations, we developed a coupled rock physics framework by integrating the MJGW partial saturation model with the Galvin fracture model, introducing a distribution coefficient to account for the non-uniform water distribution between the matrix and fractures. The coupled model accurately explains the V_p and SWS trends, while the overestimation of V_s and ε is attributed to near-dry surface effects at grain contacts and mutual interaction between fractures. This work provides experimental data and modeling insights for seismic-based characterization of multiphase-fluid-saturated fractured reservoirs.