1. adj. [Formation Evaluation]
Referring to a type of conventional electrical log in which the current emitting electrode (A) and the measure electrode (M) are placed close together on the sonde, and the current return electrode (B) and the measure reference electrode (N) far away. The response is determined mainly by the distance between A and M. The larger AM, the deeper the measurement, but the poorer the bed boundary response. Although many distances have been used, the most common are 16 in [40 cm], known as the short normal, and 64 in [162 cm], known as the long normal.
See: electrical log