US 5,309,990 AGranted

Coiled tubing injector

AssigneeHydra-Rig, Inc.

InventorRaymond E. Lance

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Abstract

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.

Claims20

Dependent claims

Apparatus for injecting and withdrawing a length of flexible cylindrical tubing into and from a well bore, comprising:

first and second sets of gripper shoes,
drive means for moving the first and second sets of gripper shoes around first and second endless paths, respectively, the paths including first and second parallel sections disposed on opposite sides of a length of the tubing during which the gripper shoes are pressed against the tubing with sufficient force to hold the tubing therebetween,
each gripper shoe including:
a base portion connected to the drive means,
at least two substantially non-deformable gripper elements each having a cylindrical gripping surface, each cylindrical surface having a radius of curvature corresponding to the outer surface of the tubing,
at least one of the gripper elements being connected to the base portion by connection means permitting movement of the element relative to the base portion between a closed position where the cylindrical gripping surface engages the tubing and an open position which facilitates engagement and disengagement of the gripping shoe elements with the tubing so as not to scuff the tubing during engagement;
wherein the connection means comprises resilient means biasing the gripper element into the open position and wherein the movable gripper elements are normally disposed in an open position with outer corners of the elements spaced apart a distance greater than the distance between the corner of the elements when gripping the tubing and are moved into closed position against the tubing in response to the gripper elements being pressed against the tubing as the gripper shoes enter the parallel sections of the endless paths and move back to the open position as the gripper elements move away from the tubing as the gripper shoes leave the parallel sections of the endless paths;
and
wherein the gripping elements, when in the closed position, apply substantially even pressure to the surface of the tubing over substantially the entire length of the gripping element so as not to substantially deform the tubing.

6 more elements

A gripper shoe for apparatus for injecting and withdrawing a length of flexible cylindrical tubing into and from a well bore, including drive means for moving first and second sets of gripper shoes around first and second endless paths, respectively, the paths including first and second parallel sections disposed on opposite sides of a length of the tubing during which the gripper shoes are pressed against the tubing with sufficient force to hold the tubing therebetween, each gripper shoe comprising:

a base portion connected to the drive means,
at least two gripper elements each having a cylindrical gripping surface, each cylindrical surface having a radius of curvature corresponding to the outer surface of the tubing,
at least one of the gripper elements being connected to the base member by connection means permitting movement of the element relative to the base portion between a closed position where the cylindrical gripping surface engages the tubing and an open position which facilitates engagement and disengagement of the gripping shoe elements with the tubing, wherein the connection means comprises resilient means biasing the gripper element into the open position, and wherein the gripping elements, when in the closed position, apply substantially even pressure to the surface of the tubing over substantially the entire length of the gripping element so as not to substantially deform the tubing.

Apparatus for injecting and withdrawing a length of flexible cylindrical tubing into and from a well bore, comprising:

first and second sets of gripper shoes,
drive means for moving the first and second sets of gripper shoes around first and second endless paths, respectively, the paths including first and second parallel sections disposed on opposite sides of a length of the tubing during which the gripper shoes are pressed against the tubing with sufficient force to hold the tubing therebetween,
each gripper shoe including:
a base portion connected to the drive means,
two substantially non-deformable gripper elements each having a cylindrical gripping surface, each cylindrical surface having a radius of curvature corresponding to the outer surface of the tubing,
each of the two gripper elements being coupled to the base portion by a resilient elastomeric means for permitting resilient movement of the gripping elements relative to the base portion in the direction of movement of the gripper shoes toward the tubing as the gripper shoes enter the respective parallel paths to engage the tubing to compensate for out-of-tolerance build-up due to manufacturing and/or wear, each gripper element applying a force to the tubing substantially along radii of the tubing so as not to deform substantially the tube.

3 more elements

Dependencies are inferred from the claim text.