Gulf Coast explorers are now frequently faced with assessing multiple-zone prospects. Some or all of these zones are often incorrectly described as "direct hydrocarbon indicators". In this paper we deal with best practices of consistency and calibration to ensure appropriate prospect valuation of such cases. Multiple-zone prospects need to be evaluated probabilistically on a zone-by-zone basis. When a zone is identified as "amplitude-bearing", a series of questions about the anomaly helps

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... s the appropriate range of uncertainty associated with productive area, net pay and recovery factor. Discussion should focus on the anomaly's (1) strength and polarity relative to known lithologic sequences and its presumed downdip water leg, (2) conformance relative to downdip structural contours, (3) AVO, and (4) fit to the depositional model.