Publications

Calibration is the key to successful amplitude vs. offset (AVO) analysis to identify fluid and lithology changes using prestack seismic data. A common AVO crossplot shows the attributes of “intercept and “gradient help to separate different lithologies and/or fluids. To move from qualitative anomaly analysis of prestack to quantitative analysis - classifying how oil, gas, or brine appear on the prestack data - it is necessary to scale the real data to the modeled synthetic data. In this paper, we consider a scaling process that matches the magnitudes of intercept and gradient events extracted from the real data to the intercept and gradient of the modeled data. After the data are properly scaled, modeling and crossplot analysis can be performed with much greater confidence. A case study is presented, demonstrating this process of matching real prestack gathers to the loggenerated gathers in a 2D crossplot. The scaled data are then used to compare anomalous interceptgradient data points that represent lithologic and/or pore fluid changes from the background data throughout the entire 3D survey.