EZDT is developed on the basis of compensation density logging instrument, and it not only could provide accurate measured value of formation density, but also could measure the photoelectric absorption coefficient, whose results are of great help in the lithology and minerals of the formation.

EZDT adopts the structure of one gamma ray source and two probes, all of which are installed on one metal plate, and such plate is clung closely on the sidewall when measuring, in such case, the counting rate of these two probes could be sent to the collection system of the ground. As the distance of these two probes away from the source is different, the mud cake has a larger influence on the probe that is closer to the source,  which provides a means to correct the influence of the mud cake on measured density value, thus measuring the volume density of the rock formation accurately.