| 摘要 |
There is provided an improved coiled tubing injector for injecting and withdrawing a length of flexible, cylindrical tubing into and from a well bore. The improved injector comprises first and second sets of gripper shoes, and drive mechanism for moving the sets of gripper shoes around first and second endless paths, respectively. The endless paths include parallel sections disposed on opposite sides of a length of the tubing. Within these parallel sections, the gripper shoes are pressed against the tubing with sufficient force to hold the tubing therebetween. Each gripper shoe includes a base portion connected to the drive mechanism and at least two substantially nondeformable gripper elements, each having cylindrical gripping surfaces corresponding to the outer surface of the tubing. A body of elastomeric material connects the gripper elements to the base portion and permits movement of the gripper elements between open and closed positions.
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