Oil Country Tubular Goods describes tubes that are used in oil and gas production: As a rule these include drill pipe, casing and tubing.
Oil Country Tubular Goods are used both onshore and offshore. In the industry, they are also referred to by the acronym OCTG (for “Oil Country Tubular Goods”). Each wellbore proceeds in multiple phases, during which
casing (lines the wellbore), and
tubing (delivery or production tubes that transport the oil and gas to the surface)
are used alternately.