OCTG Casing and Tubing Size Chart

OCTG Casing and Tubing Meaning

OCTG stands for Oil Country Tubular Goods and covers a range of pipe products that are critical to oil and gas production, especially drilling operations. These products meet API or similar industry standards and include drill pipe, steel casing, tubing, pup joints, connections and accessories for use in the onshore and offshore oil industry.

The most common term for tubular goods in the oil and gas industry is Oil Country Tubular Goods (OCTG). Oil Country Tubular Goods can be used in different ways: they may be used to extract or inject gas, oil, water, steam, etc., and can be classified as casing or tubing depending on the specific application. These pipes are made of various grades of steel and are designed to withstand the high pressures and corrosive environments encountered in oil and gas well operations. Casing is used as a protective layer to help the oil well resist corrosion from internal or external contaminants to maintain durability; tubing is used to inject or extract oil fluids. Understanding the sizes and specifications of these pipes is essential to ensure the integrity and production efficiency of the oil well.

Common sizes and specifications of OCTG casing and tubing

The following table lists the sizes and specifications of common OCTG casing and tubing:

Steel Casing Pipe Dimensions and Weight Chart

OCTG Tubing Dimensions and Weight Chart

Common standards and specifications for OCTG casing and tubing

Standard	API 5L, API 5CT, ASTM A106/A53, ASTM A519, JIS G 3441, JIS G3444, JIS G3445 DIN 2391, EN10305, EN10210, ASME SA106, SA192, SA210,SA213, SA335, DIN17175, ASTM A179
Our diameter	1/8 – 30 inch (10.3-762mm)
Wall Thickness	0.049” – 2.5” (1.24- 63.5mm)
Length	Random Length, Fixed Length, SRL, DRL
Steel Grade	API 5L: GR B, X42, X46, X56, X60, X65, X70 ASTM A53/A106: GR A, GR B, GR C ASME SA106: GR.A, GR.B, GR.C ASME SA192: SA192 ASME SA209M: T1, T1a ASME SA210: GR.A-1, GR.C ASME SA213: T2, T5, T9, T11, T12, T22 ASME SA335: P2, P5, P9, P11, P12, P22, P91 DIN17175:ST35.8, ST45.8, 15Mo3, 13CrMo44
Surface	Fusion Bond Epoxy Coating,Coal Tar Epoxy,3PE,FBE,Varnish coating,Bitumen coating,Black Oil coating as per customers requirement
Treatment	Heat treatment:Annealed: Bright annealed,Spheroidize annealed, Normalized, Stress relieved, Cold finished, Quenched and Tempered.
Application	Applicable to the general structure, mechanical structure, water wall panel, economizer, super heater, boiler and heat exchanger with seamless steel tubes, and to transport liquid, gas, oil etc.

API 5CT OCTG Pipe Grades

Mechanical Properties
Group	Grade	Type	Total	Yield Strength (Mpa)		Tensile	Hardness max
			%	min.	max.	MPa	HRC	HBW
1	H40	—	0.5	276	552	414	—	—
	J55	—	0.5	379	552	517	—	—
	K55	—	0.5	379	552	655	—	—
	N80	1	0.5	552	758	689	—	—
	N80	Q	0.5	552	758	689	—	—
	R95	—	0.5	655	758	724	—	—
2	M65	—	0.5	445	586	586	22	235
	L80	1	0.5	552	655	655	23	241
	L80	9Cr	0.5	552	655	655	23	241
	L81	13Cr	0.5	552	655	655	23	241
	C90	1	0.5	621	724	689	25.4	255
	T95	1	0.5	655	758	724	25.4	255
	C110	—	0.7	758	828	793	30	286
3	P110	—	0.6	758	965	862	—	—
4	Q125	1	0.65	862	1034	931	—	—
a. In case of dispute, laboratory Rockwell C hardness testing shall be used as the referee method.
b. No hardness limits, but the maximum variation is controlled by manufacturer acc API 5CT.

Standard and Grades: API 5CT J55 / K55, N80-1, N80Q, C90, T95, P110, Q125 and 13Cr
Casing Pipe Size range: 5 1/2 “to 20” Length usually in R3.
Tubing Pipe dimensions range: 1.0 “, 1.315”, 1.66 “, 1.9”, 2.063 “, 2 3/8”, 3 1/2 “and 4 1 /2”, Length in R2.
Type of connections for Casing: BTC (thread coupling buttress), LTC (long round thread coupling), premium connection.
Types of connections for Tubing: BTC, NUE, EUE, Premium

Main types and applications of OCTG pipes

1. Drill pipe: used to transmit power, rotate the drill bit and circulate drilling fluid during drilling. Drill pipe needs to withstand axial tension, high torque and internal pressure.

2. Casing pipe: Provide structural support in the borehole, prevent wellbore collapse, and isolate different formations. Casing usually uses large diameter pipes, meets standards such as API 5CT, and has different steel grades and thread types.

3. Tubing pipe: Used to transport oil or natural gas from the formation to the ground. Tubing needs to withstand the pressure during production and resist loads and deformation. Common tubing specifications also meet API 5CT standards and have a variety of diameters and connection types

Key factors in selecting OCTG pipes

When selecting OCTG pipes, the following factors should be considered:

Downhole conditions: including formation pressure, temperature, corrosiveness, etc. to determine the required steel grade and specifications.

Mechanical properties: Ensure that the pipe has sufficient strength and durability to withstand various stresses during drilling and production.

Connection type: Select the appropriate threaded connection type according to specific needs to ensure sealing and reliability.

Understanding the size and specifications of OCTG pipes and how to choose the right pipes according to specific applications is essential to ensure the safety and efficiency of oil and gas operations.