Changes

''Wireline units'' use special equipment ([[:file:workovers_fig5.png|Figure 5]]) on a solid wireline to gather data (pressure, temperature, and depth) and to set, manipulate, and/or retrieve tubing plugs, sliding sleeves, flow regulators, gas lift valves, safety valves, and wireline fishing tools. Wireline equipment can also be used to cut paraffin and remove wellbore fill. Prior planning, good operators, good equipment, and reasonable well conditions are prerequisites to the success of this method.

''Wireline units'' use special equipment ([[:file:workovers_fig5.png|Figure 5]]) on a solid wireline to gather data (pressure, temperature, and depth) and to set, manipulate, and/or retrieve tubing plugs, sliding sleeves, flow regulators, gas lift valves, safety valves, and wireline fishing tools. Wireline equipment can also be used to cut paraffin and remove wellbore fill. Prior planning, good operators, good equipment, and reasonable well conditions are prerequisites to the success of this method.

''Coiled tubing units'' ([[:file:workovers_fig6.png|Figure 6]]) find application in cleanout work, stimulation, plugback jobs, and unloading wells with nitrogen. Coiled tubing units can have 10,000 to [[depth::15,000 ft]] of pipe (usually 1-in. outside diameter) that can be reeled continuously into the wellbore. The pipe can be used to pump into the well and circulate fluids such as water, acid, or cement. The use of a dynadrill permits some drilling with coiled tubing. Limitations of coiled tubing include the reduced strength of the tubing and low pumping rates (high friction pressure because of the diameter and length). Coiled tubing can be run into wells against pressures up to 5000 psi.

''Coiled tubing units'' ([[:file:workovers_fig6.jpg|Figure 6]]) find application in cleanout work, stimulation, plugback jobs, and unloading wells with nitrogen. Coiled tubing units can have 10,000 to [[depth::15,000 ft]] of pipe (usually 1-in. outside diameter) that can be reeled continuously into the wellbore. The pipe can be used to pump into the well and circulate fluids such as water, acid, or cement. The use of a dynadrill permits some drilling with coiled tubing. Limitations of coiled tubing include the reduced strength of the tubing and low pumping rates (high friction pressure because of the diameter and length). Coiled tubing can be run into wells against pressures up to 5000 psi.

''Snubbing units'' ([[:file:workovers_fig7.png|Figure 7]]) use hydraulic pressure and rams to introduce small, coupled tubing into the well, if necessary, against pressures above 5000 psi. The tubing is stronger and can be rotated so that tougher cleanout or fishing jobs can be accomplished. Snubbing units are used for the same type of jobs as are coiled tubing units, but their compactness is an advantage in offshore work. They are slow and expensive, but in the right applications, they are the more economical way to accomplish the task.

''Snubbing units'' ([[:file:workovers_fig7.jpg|Figure 7]]) use hydraulic pressure and rams to introduce small, coupled tubing into the well, if necessary, against pressures above 5000 psi. The tubing is stronger and can be rotated so that tougher cleanout or fishing jobs can be accomplished. Snubbing units are used for the same type of jobs as are coiled tubing units, but their compactness is an advantage in offshore work. They are slow and expensive, but in the right applications, they are the more economical way to accomplish the task.

==See also==

==See also==