Coiled-tubing workover:

Lengths of the tubing up to 16,000 feet are stored on the surface on a reel in a manner similar to that used for wireline.

The unit is rigged up over the wellhead.

The tubing is injected through a control head that seals off the tubing and makes a pressure-tight connection.

A unique feature of the unit is that it allows continuous circulation while it is being lowered into the hole.

Terms Related to Coiled-tubing workover

• Concentric tubing workover

  A workover performed with a small-diameter tubing work string inside the normal tubing. Equipment needed is essentially the same as that for a conventional workover ...

• Hydraulic workover

  A series of hydraulic rams to restrain and pull tubing under well pressure, temporarily attached to the wellhead for workover.

• Macaroni rig

  A workover rig, usually lightweight, that is specially built to run a string of 3/4 inch or 1-inch tubing. See macaroni string.

• Tubing head

  A flanged fitting that supports the tubing string, seals off pressure between the casing and the outside of the tubing, and provides a connection that ...

• Sucker rod

  A special steel pumping rod. Several rods screwed together make up the mechanical link from the beam pumping unit on the surface to the sucker ...

• Reeled tubing

  Lighter-duty well maintenance than hydraulic workover, employing small od tubing capable of descending down the production string under well pressure

• Coiled tubing

  A long, continuous length of pipe wound on a spool. The pipe is straightened prior to pushing into a wellbore and recoiled to spool the ...