Casing is a large-diameter pipe that serves as the structural retainer for the walls of oil and gas wells or wellbore.
It is inserted into a well bore and cemented in place to protect both subsurface formations and the wellbore from collapsing and to allow drilling fluid to circulate and extraction to take place
Definition Seamless steel pipe used to sustain the wall of oil or gas well, it belongs to disposable consumable material.
Pipeline transport is the long-distance transportation of a liquid or gas through a system of pipes—a pipeline—typically to a market area for consumption.
The latest data from 2014 gives a total of slightly less than 2,175,000 miles (3,500,000 km) of pipeline in 120 countries of the world.
The United States had 65%, Russia had 8%, and Canada had 3%, thus 75% of all pipeline were in these three countries