Analyses and Judgments of Nobel Prizes in Chemistry
Authors: Tofik AHMADOV, DSc (Geol. & Mineral.), Prof & Amikishi ASADLİ, Doctoral student
DOI: DOI: 10.87349/ahuri/180132
Page No: 20-31
Abstract
This paper presents a comprehensive study of Vertical Seismic Profiling (VSP) data and Pseudo-Acoustic Logging (PAL) inversion applied to well H1856 at the Govsany hydrocarbon field located on the Absheron Peninsula, Azerbaijan. The primary focus is on the analysis and prediction of seismic velocities below the well bottom to establish a reliable depth-time relationship, which in turn was used to forecast the depths of key seismic reflecting horizons, particularly those lying beneath the Kalin Suite — the main productive formation of the field. The VSP observations, conducted with multi-component processing, demonstrated high-quality data that correlate well with acoustic logging measurements, enabling the construction of robust one-dimensional and two-dimensional velocity models to characterize the acoustic properties of subsurface formations. PAL inversion was successfully implemented using a dominant frequency range of 5 to 70 Hz, resulting in stable and adequate velocity profiles that reveal a significant velocity decrease below the well bottom. The derived depth-time model facilitated the prediction of depths for important seismic horizons, information that was crucial in guiding the drilling of the deep production well 1870. This well discovered productive reservoirs within an abnormal high-pressure zone (AHPZ) and was operated successfully before being decommissioned for technical reasons. The study underscores the importance of integrating VSP and acoustic logging data to improve the accuracy of seismic interpretation and reservoir characterization. Furthermore, it highlights the limitations of conventional inversion theories when applied to deviated wells such as H1856, emphasizing the inherent uncertainties that must be considered. For future seismic acquisition efforts, the use of vibrational seismic sources is recommended due to their stable frequency spectra across all depths, which would significantly enhance data resolution compared to impulsive sources like pneumatic chambers. Overall, the research provides valuable insights into seismic velocity modeling and horizon depth prediction in complex geological settings, contributing to optimized well placement and resource development strategies.
