a workover performed with a continuous steel tube, normally 0.75 inch to 1 inch (1.9 to 2.54 centimeters) outside diameter, which is run into the well in one piece inside the normal tubing. Lengths of the tubing up to 16,000 feet (4,877 meters) 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.