1. n. [Reservoir Characterization]

A diagram that displays multivariate data. A good choice of glyph design can aid the recognition of complex similarities or distinctions in a set of data. A well-known example of an oilfield glyph is the Stiff diagram, which shows the patterns of cations and anions in fluids.

Reference: Stiff HA Jr: The Interpretation of Chemical Water Analysis by Means of Patterns, Journal of Petroleum Technology 3, no. 10 (1951): 15-16.