Definition
Workstring — A workstring is a temporary string of pipe or tubing run into an existing well to perform completion, workover or intervention tasks — such as circulating, milling or setting tools — rather than to drill new hole.
Also known as: work string, work-string
What a workstring is
A workstring is any pipe string run into a well to do work other than primary drilling. It may be built from drill pipe, tubing, or dedicated workstring tubing, and is used during completion and workover operations — washing out fill, circulating fluids, running or retrieving downhole tools, milling, or conveying stimulation treatments.
Unlike a drill string, a workstring is often run inside casing or a completion, so its outside diameter, connection sealing and pressure integrity are chosen for the specific intervention rather than for rotary drilling.
Typical uses
- Completion — running packers, sand-control screens and other equipment to depth.
- Workover — cleaning out, circulating, and re-establishing production in an existing well.
- Milling and washover — rotating and circulating to remove obstructions or scale.
Renting a workstring
Because interventions are short-duration, most operators rent the workstring for the job. Explore workstring tubing and workover applications, or contact us to spec a string sized and pressure-rated for your intervention.