Quick core tube for boring rock during formation of well, has friction reducing unit to reduce wall friction during feeding or raising of tube, and holding elements lowered or pulled up by drill string

摘要

The tube has holding elements e.g. active steered mats, nubs, cables, friction elements, pins and arbors, for holding a rock, and a friction reducing unit to reduce wall friction during feeding or raising of the tube. The holding elements are lowered or pulled up by a drill string, where the core tube has length of about 18 m.