1. adj. [Formation Evaluation]

Pertaining to logs that measure the properties of electromagnetic waves as they move through a formation. Measurements-while-drilling (MWD) propagation resistivity logs work between about 100 kHz and 10 MHz. Dielectric propagation logs work between 20 and 200 MHz. Logs made above 200 MHz and into the GHz range are known as electromagnetic propagation logs. Below about 100 kHz, the measurements are based on the properties of standing waves, not of propagation. Induction and laterolog tools work in this range.

See related terms: dielectric propagation log,  resistivity log