What Does Casing Scraper Mean?
A casing scraper is a wellbore clean-up tool with a blade-like attachment used to remove filter cake, scale, debris and other obstructions from the internal diameter of a casing pipe. This keeps the casing pipe clean and allows downhole tools to run smoothly within the casing. Most casing scrapers are adapted to suit any casing size and drill pipe combination.
A casing scraper is generally run on tubing or drill pipe and routinely used in workover operations to ensure a clean wellbore before reinstalling the completion string. The cleaning of the casing internal diameter (ID) is a critical part of successful wellbore completion, especially for fluid filtration and the proper setting of sealing elements used in downhole tools.
Casing scrapers are designed to provide 360° coverage to ensure complete clean-up of rust, perforation burrs, scale, debris, cement, or filter cake that may be stuck to the casing pipe.
A well-executed clean-up removes any residue that can block screens and pores which can otherwise reduce wellbore productivity. It also helps reduce non-productive time during wellbore completion.
Casing cleanup is necessary whether a new well is being drilled or an old well is being reworked and is a critical part of successful completion operations. Obstructions in the casing can interfere with the operation of downhole tools during drilling, wireline jobs, fishing, or completion.
For packers, patches, and similar tools that require a grip on the casing, a clean ID is necessary for a good grip. In such areas, the casing scraper is run two or three times to ensure that the wall of the casing is clean and smooth.