What is OCTG?
It includes Drill Pipe, Steel Casing Pipe and Tubing
OCTG is the abbreviation of Oil Country Tubular Goods, it mainly refers to pipe products used in oil and gas production (drilling operations). OCTG tubing is typically manufactured based on API specifications or related standard specifications. It can also be considered a generic name for drill pipes, steel casing pipes, fittings, couplings and accessories used in the onshore and offshore oil and gas industry. To control the chemical properties and apply different heat treatments, OCTG pipes are classified into different performance materials with more than ten grades.

Types of Oil Country Tubular Goods (OCTG pipes)
There are three main types of Oil Country Tubular Goods, which include Drill pipe, Casing pipe, and Tubing pipe.

OCTG Drill pipe – Pipe for Drilling
Drill pipe is a heavy, seamless tube that rotates the drill bit and circulates drilling fluid. It allows the drilling fluid to be pumped through the bit and back up the annulus. The pipe can withstand axial tension, extremely high torque and high internal pressure. That is why the pipe is extremely strong and vital in OCTG endeavour.
Drill Pipe normally means the Durable steel pipe used in drilling, standards in API 5DP and API SPEC 7-1.
If you don’t understand the annulus of oil well, it is the space between the casing and the piping or any piping tubing, casing or piping immediately surrounding it. Annulus allows the fluid to circulate in the well. So when we are talking about strong or heavy-duty OCTG pipe, we are talking about Drill pipe.
Steel Casing pipe – Stabilize the wellbore
Steel casing pipes are used to line the borehole that is being dug into the ground to get oil. Just like the drill pipe, the steel pipe casing can also withstand axial tension. This is a large-diameter pipe inserted into a drilled borehole and held into place with cement. The casing is subject to the axial tension of its dead weight, the external pressure of the rock surrounding it, and the internal pressure of the purging fluid. When it is well cemented in place, the drilling process is aided in the following ways:
· Casing sticks the drill string and prevents unstable upper formation from caving in.
· It prevents water well zone contamination.
· It allows smooth internal bore for manufacturing equipment installation.
· It avoids contamination of the production area and loss of liquid.
· It isolates the high pressure area from the surface
· And more

The casing is an extremely heavy-duty pipe vital to OCTG.
OCTG Casing Pipe standard
Steel Casing pipe standards usually referred to API 5CT, Common Grades in J55/K55, N80, L80, C90, T95, P110 etc. Common length in R3 which nominal at 40 ft / 12 meters. Casing pipe ends connection types are usually in BTC and LTC, STC. And premium connections are also required in large quantities in an oil and gas piping project.
Steel Casing Pipe Price
The cost of steel casing pipe is lower than drill rod or OCTG pipe price, which is usually 200 USD higher than regular API 5L pipe. Consider the cost of threads + joints or heat treatment.
OCTG Pipe – Transporting oil and gas to the surface
OCTG Pipe goes inside the casing because this is the pipe through which the oil escapes. Tubing is the simplest part of the OCTG and typically comes in 30 ft (9 m) sections, with threaded connections at both ends. This pipeline is used to transport natural gas or crude oil from production areas to facilities where it will be processed after drilling is completed.
The tube must be capable of withstanding the pressures during extraction and withstanding the loads and deformations associated with manufacturing and repackaging. Just like how the shell is made, the tubes are also made in the same way, but an additional mixing process is applied to make it thicker.
OCTG Pipe Standard
Similar to the shell pipe standard, the OCTG pipe in API 5CT also has the same material (J55/K55, N80, L80, P110, etc.), but the pipe diameter can be up to 4 1 /2″, and it ends up in different types like BTC, EUE, NUE, and premium. Usually, EUE’s thicker connections.