| 主权项 |
1. A coiled tube injection drive assembly comprising a pair of opposed, upwardly extending movable carriages positioned in opposed fashion so that portions of tubing may be vertically disposed and engaged between the movable carriages, each of the movable carriages comprising a respective gripper chain assembly comprising:
an endless gripper chain for engaging a respective side of the portions of tubing, the gripper chain being mounted on (a) a first gripper chain sprocket mounted on a motor-driven first shaft, and (b) an second gripper chain sprocket mounted on a second shaft, the first shaft and the second shaft being spaced apart with their longitudinal axes in substantially parallel alignment, one being disposed above the other such that the endless gripper chain when rotated about the first gripper chain sprocket and the second gripper chain sprocket moves within a plane vertically oriented relative to the surface of the earth during use; an endless bearing chain, a bearing portion of which is deployed between a vertically disposed, substantially linear race and an inner surface of a tube-contacting portion of the endless gripper chain, whereby the bearing portion of the bearing chain is biased in a linear vertical path against the inner surface of the tube-contacting portion of the endless gripper chain; and a first linear bearing sprocket coaxially disposed between a pair of spaced apart drive sprocket wheels formed by the first gripper chain sprocket, and a second linear bearing sprocket coaxially disposed between a pair of spaced-apart second gripper chain sprocket wheels formed by the second gripper chain sprocket, wherein the first linear bearing sprocket is not fixedly mounted to the motor-driven first shaft but is disposed concentrically around the motor-driven first shaft;wherein each gripper chain of one of the pair of opposed carriages is opposed to the gripper chain of the other one of the pair of opposed carriages, and is rotated, through its respective first gripper chain sprocket and respective motor-driven first shaft, in counter-rotation with respect to the gripper chain of the other one of the pair of opposed carriages, so that when the tubing is engaged by and between the opposed gripper chains of the pair of opposed carriages while the opposed carriages are biased toward one another, the tubing may be (i) injected downwardly into a well or extracted upwardly from the well by the motor-driven counter rotation of the gripper chains of the opposed carriages while the gripper chains contact opposing sides of the tubing, and/or (ii) held in place in a fixed position for a period of time. |
