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.