Scratchers use metal wires to scrape mud cake off permeable zones to help obtain a solid cement column.
Bow-spring centralizers consist of an ease of passage way through narrow hole sections with expansion in targeted locations.
Semi-rigid centralizers are composed of double crested bows, providing restoring forces that exceed standards set forth in the API specifications.
Its blade length, angle and spacing can be designed to fit specific well applications, especially for the close tolerance annulus.
The inside (including the external taper) is usually made of cement or thermoplastic, since this material must be drilled out if the well is to be deepened beyond the casing point.
[3] The check-valve assembly fixed within the float collar prevents flow back of the cement slurry when pumping is stopped.
A series of differently sized rubber plugs pumped down inside the casing open and then later close the sliding valves.