Types Of Casing Pipe

Casing is used to line complete boreholes that have been dug into the ground for oil. OCTG casings are large diameter pipes that are cemented into a borehole. General speaking, there are 6 types of casing pipe used in onshore and offshore wells, which are as follows:

Structural Casing

Structural Casing can solve problems of additional lost circulation, hole caving and minimize kick problems from shallow gas zones. Typical depths range from 600 - 1000ft.

Conductor Casing

Conductor casing is used to support the well by preventing collapse of the loose soil near the surface during drilling operations. It's diameters varies from 18 to 30''.

Surface Casing

There are some strict regulations in some countries due to environmental issues. Surface casing can isolate freshwater zones from oil well so that these areas are not contaminated during drilling and completion.

Intermediate Casing

Usually, intermediate casing is the longest section of casing in a well. Intermediate casing is used to minimize hazards that underground formations may pose to a well. It also helps to maintain hydrostatic pressure at a appropriate level to prevent blowouts.

Production Casing

Production casing is the final interval and the deepest section of casing in a well. It can provide a conduit from the petroleum producing formation right up to the surface.

Casing Liner

Essentially, casing liner is a string of intermediate casing that does not extend all the way to surface. It is hung off in or above the previous casing shoe and is usually cemented over its entire length to ensure it seals within the previous casing string.