新奥2025年精准资料完整合集

Abstract: The characterization of subsurface formations via the analysis of near-wellbore velocity profiles represents a crucial method in geophysical exploration. This technique enables the evaluation of key parameters, including rock brittleness, wellbore stability, fracturing effects, and invasion extent, thereby enhancing comprehension of formation structures and informing exploration strategies. However, traditional near-wellbore formation velocity imaging methods exhibit two principal limitations. First, these methods lack azimuthal sensitivity, yielding results averaged across all directions. Second, they are computationally intensive and impractical for well-site environments. To address these drawbacks, we developed a rapid 3D velocity imaging method for array acoustic logging instruments equipped with azimuthal receivers, capable of producing 3D imaging results efficiently. The workflow entails the following steps: (1) Band-pass filtering of logging data to mitigate scattered wave interference caused by formation heterogeneity near the wellbore; (2) combination of receivers with varying detection ranges in each direction to derive radial velocity sequences, followed by integration of ray-tracing theory to obtain 2D velocity distributions; and (3) synthesis of final 3D velocity imaging results via interpolation of these 2D datasets. In the velocity sequence extraction process, we significantly reduced the computational load by employing an adaptive time window, ensuring rapid and stable application in well-site settings. We utilized the finite difference method to construct well models with heterogeneous formations. The compressional and shear wave 3D velocity imaging results derived from synthetic data correlated with the model, demonstrating the azimuthal sensitivity of our proposed method. Furthermore, we applied this method to a well in West China, successfully identifying the azimuth of near-wellbore anisotropy.