METHOD OF DISCONNECTING A DRILL STRING AT A DRILL RIG

摘要

Method and apparatus for disconnecting an end rod (115) from a drill string (100) coupled together by a threaded connection (604, 605). Rod handling apparatus (102) comprises a gripper unit (106) having a 'floating'sled (206) with a sensor unit (208) configured to monitor relative axial position of the sled relative to a frame (205) of the gripper unit to determine a decoupling of the threaded connection and a separation of an end rod from the drill string.