ULSEL. A well log recorded with the use of a modified [[long normal curve|long normal]] electrode configuration mounted on a 5,000-foot [[bridle]]. The [[AM spacing]] can be made 75, 150, 600, or 1,000 feet. Differences between the measured [[resistivity|resistivities]] and anticipated resistivities calculated from conventional [[resistivity log|resistivity logs]] indicate nearby resistivity anomalies. Used to define the distance to a salt dome flank. May have important application in locating salt overhangs or casing in nearby well bores.