دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: see well velocity survey.

n: measures the time needed for a sound pulse generated at the surface to reach successive selected depths in the borehole. Used to correct problems in downhole acoustic logs caused by filtrate invasion of the formation and borehole irregularities. Also used to calibrate depths on seismic sections.