The "compensation" measurement method is generally used for three porosity logging methods: acoustic time difference, density and neutron porosity.

When the controlled acoustic vibration source is put into the well, the sound wave emitted by the sound source causes the vibration of the surrounding particles and produces body waves-longitudinal waves and shear waves in the stratum; Induced interface waves-pseudo-Rayleigh waves and Hiragi waves are generated at the borehole wall-drilling fluid interface. As the carrier of formation information, these waves are received by underground receivers and sent to the ground for recording, which is called acoustic logging. The basis is that different rocks have different acoustic differences.