1. n. [Formation Evaluation]

A device that helps to keep a wireline logging tool away from the center of the borehole. Typical devices are a single bow spring mounted on the outside surface of the logging tool or a set of rubber fingers mounted at the bottom. Some measurements, such as induction logs, respond better when the tool is eccentralized, while others, including acoustic logs, are better when centralized.

Antonyms: centralizer

See: acoustic log,  logging tool