Dictionary:Ultra-long spaced electric log (ULSEL)
A modified long-normal borehole log mounted on a 5000 ft bridle. The A to M spacings are 75, 150, 600, and 1000 ft. Differences between the measured resistivities and anticipated resistivities calculated from conventional resistivity logs indicate nearby resistivity anomalies, such as a salt-dome, or nearby hydrocarbons. Has been used to sense casing in a blow-out well from an approaching relief well.