The choice between the types of casing and casing sizes to be run and cemented is dictated by the well design and therefore outside the scope of this article. However, to improve the chances of achieving successful primary cementation several items of auxiliary equipment are incorporated in the string as Cementing Tools .

Float Equipment
These cementing tools are usually placed two joints above the shoe. Sometimes the float collar is combined in a float shoe. Its purpose is that of a check valve preventing backflow after the cement has been placed in the annulus and retaining the cement interface inside to ensure good cement around shoe. This is done most of the time by a spring-loaded ball or flapper suitably seated to seal.

Cementing Head Tool
After running and setting in the rotary table slips, a cementing head is mounted on top of the casing. This tool also contains one or more plugs to separate cement, pre-flushes) etc., from mud before and after pumping/displacement. The plugs are retained in the cementing head by pins or bars, which are pulled out at the appropriate time to release the plug, or bails, which are rotated to drop a plug. Plugs are moved by switching to the appropriate fluid connections on the head.

Cementing Plugs
Plugs available from cementing service companies come in a variety of shapes and sizes. The selection of plug(s) for a particular job should be guided by local experience. One feature to be considered is the rotation of plugs when drilling out. Nowadays plugs (and floats) are available that have been manufactured with a serrated top and or bottom profile, permitting the plugs to lock when seated.