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. Generally, there are six types of casing pipes used in onshore and offshore wells, as follows:

Structural Casing

Structural Casing can solve problems of lost circulation, hole caving and kick problems from shallow gas zones. Depths typically range from 600-1000ft.

Conductor Casing

Conductor casing supports the well during drilling operations by preventing collapse of loose soil near the surface. Its diameter typically ranges from 18 to 30 inches.

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.