Research on Reconstruction and Application of Acoustic Logging Curves Based on Rock Volumetric Physical Model

Compressional slowness (DTC) and shear slowness (DTS) are indispensable basic data for the study of petrophysics and geomechanics in oil and gas fields. In this paper, aiming at the tight sandstone reservoirs where DTC and DTS are seriously lacking, the method of rock volume physical model is proposed to reconstruct the DTC and DTS. Individualized petrophysical models characterizing DTC and DTS have been established specifically for tight sandstone reservoir. The DTC and DTS values of individual components were determined through an integrated experimental-theoretical analytical approach, thereby establishing predictive reconstruction models for both P-wave and S-wave slowness. Core-scale and wellbore-scale reconstruction were successfully achieved, with validation conducted through comprehensive comparative analysis. The reconstructed acoustic curves were subsequently applied to geomechanical parameter derivation and in-situ stress quantification, demonstrating computational accuracy through field measurement verification. Key findings reveal: (1) The DTC model architecture comprises four-phase constituents (argillaceous content, bound fluid, matrix framework, and mobile fluid), whereas the DTS model incorporates binary components (argillaceous material and matrix); (2) Reconstruction fidelity was evidenced by sub-5% relative errors in core-scale slowness reconstruction and 3.37–4.65% relative deviations in well-log syntheses compared to physical measurements; (3) Geomechanical validation showed horizontal stress calculations deviating -0.22–0.36 MPa from measured values, confirming engineering applicability; (4) This reconstruction paradigm proves particularly effective for mature logging suites deficient in acoustic data, establishing a new theoretical framework for acoustic log synthesis in data-constrained reservoirs. The methodology provides a viable technical pathway for enhanced geomechanical characterization in unconventional tight sandstone plays.