Oil casing is a steel pipe used to support the walls of oil and gas wells, ensuring the normal operation of the entire well during and after the drilling process. How many layers of casing should be used for each well based on different drilling depths and geological conditions. After casing is lowered into the well, cement cementing should be used, which is different from oil pipes and drill rods and cannot be reused. It is a disposable consumable material. So, the consumption of casing accounts for over 70% of all oil well pipes.