Utilization of Electrical Plasma for Hard Rock Drilling ...- milling cement casing ,They are related to plasma milling of cement behind casing in well conditions, cement contamination by water-and oil-based drilling fluids as well as influence of eccentricity between tubing and ...Oil and Gas Well Drilling and Servicing eTool | Glossary ...cement n: a powder consisting of alumina, silica, lime, and other substances that hardens when mixed with water. Extensively used in the oil industry to bond casing to the walls of the wellbore.