Abstract:
In hydrocarbon exploration and exploitation, reservoir thickness represents a fundamental parameter for reservoir characterization and serves as a direct determinant of both the material foundation and developmental potential of hydrocarbon reservoirs. Therefore, this parameter is vital for the exploration and exploitation of these reservoirs. In recent years, geophysical technicians have developed a variety of pre-stack and post-stack seismic techniques for reservoir thickness prediction. However, these techniques, despite significantly improving the prediction accuracy, suffer from specific application limitations. Given the limited exploratory wells during early-stage hydrocarbon exploration and exploitation, this study investigated the seismic response characteristics of the reservoir model based on the classical Widess wedge. Accordingly, two reservoir parameters were introduced: band-limited wave impedance and seismic net-to-gross ratio, and their functional relationship was determined. Then, a three-step technique for reservoir thickness prediction was developed based on band-limited wave impedance. The tuning effects of seismic wavelets were eliminated using a detuning correction factor for wavelet amplitude, significantly enhancing the prediction accuracy of the proposed technique. The proposed technique reduces the significant prediction errors inherent in conventional seismic amplitude-based methods when the reservoir thickness exceeds one-fourth of the dominant wavelength. Meanwhile, it enhances prediction accuracy for thin reservoirs with thicknesses of less than one-eighth of the dominant wavelength. Therefore, this technique holds great application potential for sandstone reservoirs formed under stable geological deposition. Furthermore, it can improve the success rate of encountering sand bodies during drilling in deep-water turbidite sandstone reservoirs and enhance the geological modeling precision of reservoirs. This technique has delivered excellent performance in application to the exploration and exploitation of deep-water turbidite reservoirs in the Lower Congo Basin.