Bow Spring Centralizers are devices fitted with hinged collars and bow springs that help to keep the casing or liner in the center of the wellbore to help ensure efficient placement of a cement sheath around the casing string.
If casing strings are cemented off-center, there is a high risk that a channel of drilling fluid or contaminated cement will be left where the casing contacts the formation, creating an imperfect seal.
Bow spring centralizers consist of an ease of passage way through narrow hole sections with expansion in targeted locations.