Slickline is a unique strand wire to run tools into wellbore. It also describes a slickline truck or doing a slickline job. Slickline was originally called measuring line, because the line was flat like a tape measure, and marked with depth increments so the operators would know how deep in the hole they were.
Slickline is often used in the oil and gas industry to lower and raise downhole tools for maintenance.
Slickline looks like a long, smooth, unbraided wire, often shiny, and comes in varying lengths. The disadvantage of a smaller diameter slickline is the lower strength. The larger the size, and higher the grade, generally means the higher line tension can be pulled before the line snaps at the weakest spot. If the tools are stuck, and the operator pulls too hard, the line will snap or pull apart at the weakest spot. When the slickline parts, this can create an expensive ‘fishing’ job, when the operator has to use different tools to catch and pull the components. Braided line is often used when the strength of slickline is insufficient and for heavy fishing such as retrieving broken drill pipes.
Slickline tools operate with a mechanical action, controlled from surface in the wireline trucks operators compartment. Typically, this mechanical action is accomplished by the operation of jars. There are generally two types of jars: mechanical and hydraulic.
Some slickline tools include: gauge cutter, downhole bailer, jar, stem, lead impression block, pulling tools, sample bailer, stroke bailer, hydrostatic bailer, running tools.