Well-to-Seismic Tie and Wavelet Extraction
Establish a precise time-depth relationship and extract a representative source wavelet.
Part 1/3 — Advanced Theory & Mechanics
The foundational efficacy of seismic inversion rests upon the fidelity of the well-to-seismic tie and the subsequent extraction of a representative wavelet. This process serves as the bridge between the depth-domain measurements of petrophysical boreholes and the time-domain observations of the seismic volume. By integrating sonic ($\Delta t$) and bulk density ($\rho_b$) logs, geophysicists derive the acoustic impedance ($Z_p = V_p \cdot \rho$), which is then converted into a reflectivity series via the Zoeppritz equations or their linear approximations, such as the Aki-Richards or Shuey formulations. The primary objective is to resolve the vertical misalignments induced by velocity anisotropy, dispersion, and the inherent differences between the high-frequency $(\sim 10^4 \text{ Hz})$ sonic tool measurements and the bandwidth-limited $(\sim 10^1–10^2 \text{ Hz})$ seismic signals.