The separation of layers is carried out by cementing the annular space of part or all of the drill casing, which used a variety of oil-well cements.
Oil-well cement is called the product made from the binders (Portland cement, slag, plastic, etc.), mineral (quartz sand, clay, etc.), which after mixing with water or other liquid provides a solution that hardens and then in the form of a stone due to the physical properties.
Cementation is called the process of substitution of the drilling fluid in a given interval of a well annulus grouting, as a result of hardening of which there is formed a solid, virtually impenetrable stone. Methods of cementing depending on geological and technical conditions are very nodiverse.
The most common type is the single stage cementing, when all of the liquid cement slurry is pumped into the annular space via the Shoe of the drill string at one time.
The quality of cementing evaluate the test casing to the drill string for leaks.