Legal Definitions - casing

Definition: Casing refers to the pipe that is cemented into place in a wellbore hole to prevent pollution and protect the hole. There are different types of casing used in oil and gas drilling:

• Surface casing: This is the first pipe set in the hole and it protects groundwater from pollution caused by drilling and producing operations.
• Intermediate casing: This casing protects deep formations from pollution caused by drilling and producing operations.
• Production casing: This is the last pipe set in the hole and it is used to produce oil and gas from the wellbore.

For example, when drilling a well for oil and gas, the first pipe set in the hole is the surface casing. This casing is cemented into place to protect the groundwater from pollution. The intermediate casing is then set in place to protect deeper formations from pollution. Finally, the production casing is set in place to produce oil and gas from the wellbore.