Schemes are a collection of fill styles, text, line, and symbol properties that apply to a log when the keyword in the table matches the keyword for a set of these properties. A scheme can be saved to an SCH file. A simple example would be scheme with a Sandstone scheme item and a Limestone scheme item. The scheme item for Sandstone may have a fill style of solid red with 50% opacity, but it also has text and line properties. Limestone would have a different set of fill, line, and text properties. For intervals where the keyword column in the table says Limestone, the limestone properties are applied to the log, and the same applies to Sandstone.
Updated July 11, 2016