FIGURE 1. (A) The Diana Subbasin is located in the western Gulf of Mexico 255 km (160 mi) south of Galveston. (B) Prior to the 1990s, no wells had been drilled in the Diana Subbasin. Today, however, five discoveries have been made in ExxonMobil's operated blocks. (C) Combined structure and composite amplitude extraction for the upper Pliocene A-50 reservoir. Structural contours are in 60-m (200-ft) intervals. Seismic amplitude extractions display distinct stripes in the in-line direction. This complicates any quantitative attribute analysis of the reservoir and restricts the application of seismic amplitude map patterns to delineate sand-body dimensions.