Method of disconnecting a drill string at a drill rig
AssigneeSandvik Intellectual Property AB
InventorsJohan JELGERT, Lars-Erik LARSSON, Per VILEN, Kent EVERMARK
Life of this patent
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Abstract
A method and apparatus for disconnecting an end rod from a drill string coupled together by a threaded connection is provided. A rod handling apparatus includes a gripper unit having a floating sled with a sensor unit configured to monitor relative axial position of the sled relative to a frame of the gripper unit to determine a decoupling of the threaded connection and a separation of an end rod from the drill string.
Claims15
A method of disconnecting an end rod from a drill string coupled together by a threaded connection, the method comprising:
- initially rotating the end rod relative to a remaining drill string in a disengagement direction of the threaded connection to partially disconnect the end rod from the drill string;
- moving a gripper unit into engagement with the partially disconnected end rod, the gripper unit having a frame and a sled suspended at the frame to be axially slidable relative to the frame, the sled having rod engagers to engage and hold the end rod;
- further rotating the end rod in the disengagement direction via the rod engagers to further decouple the end rod from the drill string;
- and
- monitoring a relative axial position of the sled at the frame using at least one sensor to determine a decoupling of the threaded connection and a decoupling of the rod from the drill string.
A drill rod handling apparatus cooperative with a drill rig to a rod to and from a drill string created by the drill rig, the apparatus comprising:
- a gripper frame;
- a sled mounted at the frame via at least one runner (207) capable of sliding movement relative to the frame in an axial direction of the rod to be transported by the apparatus;
- a bias component to bias the axial sliding movement of the sled relative to the frame;
- rod engagers mounted at the sled to engage and hold the rod to be transported;
- a sensor positioned at the sled or frame configured to monitor a relative axial position of the sled relative to the frame, wherein the bias component includes at least one first bias component positioned to bias the sled to be resistant to an axially forward movement of the sled along the at least one runner and at least one second bias component positioned to bias the sled to be resistant to an axially rearward movement of the sled along the at least one runner.
Dependencies are inferred from the claim text.