Cementing a well is a procedure of developing and pumping cement into a wellbore. Cement protects the wellbore, permanently shuts off water penetration into the well, seals the annulus after a casing has been run into the wellbore, and finally seals lost circulated zones. In directional drilling, cementing may be used to plug an existing well and run a directional well from that point. Also cementing is used to plug a well to abandon it. The process of operation is that the cement slurry is deployed into the well via pumps and drilling fluids are displaced with cement. The cement slurry flows to the bottom of the wellbore through the casing. It fills the space between casing and the actual wellbore .This creates a seal as well as permanently positions the casing in place. Special tools, pumps, and mixers are used, including hydraulic jet mixers, re-circulation mixers or batch mixers used to mix dry cement with water to create slurry and pump it down.