Casing VS Tubing

Tubing and casing pipe both belong to OCTG, which are essential tools for oil exploration, development and production. But what are the differences between tubing and casing pipe? You may know the answer after reading the following passage.

What Is Casing Pipe?

Casing pipe is used for lining the complete borehole which has been dug into the ground to procure oil. Oil well casing pipe need to be made from high quality strong steel material as it is subjected to axial tension.

OCTG casing pipe is cement sealed in the borehole to stabilize the well, keep contaminants and water out of the oil stream, and prevent oil from leaching into the groundwater.

What is Tubing?

Tubing pipe is inserted inside the wellbore through the casing pipe, which helps the transportation of the hydrocarbons to the surface. OCTG tubing can be used for natural gas or crude oil transportation to facilities for further processing after drilling is completed.

Oil well tubing can protect oil well casing from wear and tear from corrosive fluids, sand, paraffin etc. And more, OCTG tubing can be replaced when damaged, which is not possible in case of OCTG casing.

What Are Differences Between Casing And Tubing?

Casing pipe is generally installed in wellbore and is cemented in place to prevent wellbore collapse, cross flow of fluids between different reservoirs and to control abnormal formation pressures.

Tubing pipe is run after drilling, which is usually run inside casing (cased hole) pipe and used as a conduit through which oil and gas is produced. It is normally a pipe inside casing which is applied to produce reservoir fluids.