Paleoscan Stratigraphy vs Proportional Layering N-S. North-south cross-section through Midland Farms Unit showing acoustic impedance (lower values in red, higher values in blue). Vertical units are in milliseconds. 3D seismic survey inline and crossline values are shown at the top. The upper and lower purple horizons form the boundaries of a proportionally subdivided zone defined in a 3D geocellular model. The red profiles are horizons extracted at the tops and bases of three separate proportional layers. The green horizons are horizon profiles generated using Paleoscan. This figure shows the value of generating model-based, high-resolution seismic horizon interpretations using next-generation tools like Eliis Paleoscan. Note that the proportional horizon profiles near the top of the zone, closer to the upper reference horizon, more closely match the profiles of the Paleoscan generated horizons. The deeper horizon profiles of the proportional layers (red) - further removed from their reference horizons, are significantly different from the individually-generated Paleoscan horizons (green). The contrast between the two interpretations illustrates the disadvantage of using proportional layering methods over thick intervals. Seismic data courtesy of Fasken Oil & Ranch Limited. 3D geocellular model created in Schlumberger Petrel.