Amplitude semblance and its fusion with the third-generation coherence for characterization of fractured-vuggy carbonate reservoirs

Abstract

Abstract In the Tarim Basin, the main hydrocarbon reservoirs of Ordovician carbonate rocks are fractured-vuggy reservoirs, of which the underground river type reservoirs are an important type. Seismic coherence attribute can highlight seismic discontinuity caused by tectonic movements, reservoir boundaries, sedimentary body boundaries or other factors. Thus, it is a widely used key technique in seismic interpretation. There are many algorithms to determine the coherence. Typically, the coherence algorithm based on eigen-structure analysis is the most robust, but is sensitive to waveform differences and insensitive to amplitude differences. This paper proposes an amplitude coherence attribute to measure semblance of root-mean-square (RMS) amplitudes of multiple traces and fuses it with the third-generation coherence (C3) to describe the boundary of underground river. Model test and case study prove that the proposed fused algorithm can effectively identify the amplitude and waveform differences in seismic data.