Abstract

A relatively new method of Phase Decomposition (Castagna et al. 2016, Chopra et al. 2023) is critical to for the analysis of lateral changes in thin layers with respect to the contemporary technology and techniques. Phase Decomposition is a novel technique that decomposes a composite seismic signal into different phase components, which can improve reservoir characterization. The technique is particularly useful in those areas where thin-bed interference causes the phase of the input seismic response to differ from the phase of the embedded wavelet in the data. For a zero-phase wavelet in the data and thin low-impedance layers below tuning thickness, the −90° phase component stands out anomalously. A corresponding high-impedance thin layer exhibits a similar +90° phase component response. Furthermore, for thin layers, a change in impedance is best seen on these plus or minus 90° components. By generating a synthetic response with use of well data and a zero-phase wavelet, such observations for thin reservoir layers can be understood with confidence and correlated with real seismic data. The original spatial distribution and lateral extent of amplitude anomalies may vary after phase decomposition, allowing the interpreter to better assess and prioritize target amplitudes and can be effectively used as a direct hydrocarbon indicator (DHI). Thus, combination of output of phase decomposition and AVO modelling will provide a better prospect level de-risking workflow in exploration and development.