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| Oil Country Tubular Goods (OCTG) |
Oil country tubular goods (OCTG) is a family of seamless rolled products consisting of drill pipe, casing and tubing subjected to loading conditions according to their specific application. (see Figure 1 for schematic of a deep well):
- Drill pipe is heavy seamless tube that rotates the drill bit and circulates drilling fluid. Pipe segments 30 ft (9m) long are coupled with tool joints. Drill pipe is simultaneously subjected to high torque by drilling, axial tension by its dead weight, and internal pressure by purging of drilling fluid. Additionally, alternating bending loads due to non-vertical or deflected drilling may be superimposed on these basic loading patterns.
- Casing pipe lines the borehole. It is subject to axial tension by its dead weight, internal pressure by fluid purging, and external pressure by surrounding rock formations. Casing is particularly exposed to axial tension and internal pressure by the pumped oil or gas emulsion.
- Tubing is pipe through which the oil or gas is transported from the wellbore. Tubing segments are generally around 30 ft [9 m] long with a threaded connection on each end.
Typical OCTG manufacturing processes include (all dimensional ranges are approximate)
- Tubing Pipe - Seamless Steel Tubing manufactured to API 5CT Specification Latest Edition, EUE Threaded and Coupled
- Casing Pipe - Seamless Steel Casing manufactured to API 5CT Specification Latest Edition, Plain End
- Carbon and Alloy Line Pipe, Welded (60” O.D. and greater), Seamless (up to 24” O.D.), High-pressure and Low-temperature; (ASTM A106, API grades X70 and higher)
- API Pipe Couplings
