1. n. [Formation Evaluation]

A log run for the purpose of correlating between wells. The most common logs used for this purpose are the gamma ray, the resistivity and the acoustic log; the most common depth scales are 1/500 and 1/1000, or 2 in/100 ft [5 cm/30 m] and 1 in/100 ft [2.5 cm/30 m].

See: acoustic log,  base log,  composite log,  detail log,  gamma ray log,  resistivity log