1. n. []

A characteristic of a model of a reservoir that may or may not vary with respect to position or with time. Porosity is a petrophysical parameter (or characteristic) that varies with position.

2. n. []

A variable that is given a constant value for the purposes of certain calculations. For example, during log analysis of a particular layer of a reservoir, the water resistivity (Rw) may be set to a particular value and referred to as a parameter.