1. n. [Formation Evaluation]

A particular type of induction log designed to read an intermediate distance into the formation while maintaining good vertical resolution. The medium-induction array of eight coils (IM) is produced by three transmitters and five receivers running at 20 kHz. A small fourth transmitter coil was added in tools built since 1968. The midpoint of the integrated radial geometrical factor is 30 in. [76 cm] in radius. The vertical resolution is about 4 ft [1.2 m] but varies with conditions. The IM is combined with a deep-induction log on the same sonde to produce a dual induction log.

Alternate Form: medium induction