A bladed or bow spring tool that helps center tools or pipe in the wellbore.
A mechanical device to position casing concentrically in the wellbore.
A centralizer is usually used during cementing operations to provide a constant annular space around the casing, rather than having the casing lying eccentrically against the borehole wall.
For straight holes, bow spring centralizers are sufficient and commonly used.
For deviated wellbores, where gravitational force pulls casing to the low side of the hole, more robust solid-bladed centralizers are better if hole conditions allow their use.
see also casing centralizer, bow spring centralizer, hydraulic centralizer, rigid centralizer, screen centralizer, solid body centralizer.