دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a device used to determine the angle and direction by which a wellbore deviates from the vertical. After the instrument is run into the hole, it takes a photograph that is then brought to the surface, developed, and analysed. Photographic survey instruments can be single-shot or multishot and magnetic or gyroscopic.