Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. In the context of formation, cement is a formation binding agent (calcite, clay, silica overgrowth, heavy oil, etc.) that hold the formation grains together. In the context of completions, cement is typically the Portland, silicate, and/or pozzilin, etc., mixtures used to form a stone-like permanent seal between the pipe and the formation.