There are five principal types of casing string:

- Stove Pipe, Marine Conductor or Foundation Pile
- Conductor Casing
- Surface Casing
- Intermediate Casing/ Liner
- Production Casing/ Liner

Surface string

The purpose of the surface string is to provides blowout protection during drilling. Setting depth is often chosen to isolate troublesome formations, loss zones, shallow hydrocarbons, water sands, or…


A liner (other than slotted liners) is a string of casing which does not extend all the way to the surface. Liners are installed to permit deeper drilling, to separate the productive zones from the…

Intermediate string

Intermediate string

The intermediate string is a string which is used to isolate weak formations, to case off loss zones, sloughing, caving and reservoir formations. Such strings are also set in transition zones to…

Production string

Production string

The Production string is a string which is installed to separate productive zones from other reservoir formations or for testing purposes.

  • The string through which the well will be completed,…

Stove pipe, marine conductor or foundation pile

The purpose of Stove pipe, marine conductor or foundation pile is to:

- protect the incompetent surface soils from erosion by the drilling fluid.

- reduce the wave and current loads imposed on the…

Conductor string

Conductor string is a string which is installed to cover unconsolidated formations, to seal off shallow water sands and to provide protection against shallow gas flows. The string is cemented to the…