Offset-amplitude variation and controlled-amplitude processing

Abstract The partition of plane seismic waves at plane interfaces introduces changes in seismic amplitude which vary with angle of incidence. These amplitude variations are a function of the elastic parameters of rocks on either side of the interface. Controlled-amplitude processing is designed to obtain the true amplitude information which is geologic in origin. The offset-amplitude information may be successfully used to predict the fluid type in reservoir sands.Various tests were carried out on a seismic profile from the Gulf Coast. The processing comparison emphasized the effects and pitfalls of trace equalization, coherent noise, offset, and surface-related problems. Two wells drilled at amplitude anomaly locations confirmed the prediction of hydrocarbons from offset-amplitude analysis. Furthermore, controlled-amplitude processing provided clues in evaluating reservoir quality, which was not evident on the conventional relative amplitude data.