1. n. [Formation Evaluation]
A conventional electrical log with very long electrode spacing. The ultralong-spaced electrical log (ULSEL) is a normal device with a distance between the current-emitting electrode and the measure electrode of between about 75 ft [23 m] and 1000 ft [305 m]. The long spacings are designed to locate objects within tens of feet of the borehole. These objects may be a salt dome or casing, in the case of a relief well.