OCTG (Tubing and Casing)

OCTG (Tubing and Casing)

OCTG (Oil Country Tubular Goods) refers to a group of rolled metal products used in the oil and gas industry, including casing and tubing. They are indeed used in the drilling process.

Casing is a term that refers to the tubing that is installed inside a drilled well to protect and support the well stream. The Casing completely surrounds the wellbore, protecting the soil layers and, most importantly, the groundwater from contamination by drilling mud and frac fluids. Additionally, it stabilizes the wellbore, which means that the casing must be able to withstand extremely high loads.

Why choose tuspipe?

Since 1998, Tianjin United Steel Pipe Co., Ltd (TUSPIPE) has been committed to supplying high-quality line pipes.

With over 500,000 tons annual production capacity, the company serves various fields and industries, such as oil & gas exploitation and transmission, ship & auto-building, water & electricity, environmental protection, mechanical engineering, infrastructure construction and etc.

TUSPIPE places a premium on product quality and rigorous product quality control. In order to maintain good product quality, the company has established a Test & Inspection Center since 2004. With a series of state-of-the-art tests and inspection equipment, the test & inspection center is able to perform the tensile tests, hydro tests, impact tests, DWTT, etc.

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Production Standard of OCTG (Tubing and Casing)

API 5CT specified that casing and tubing used in OCTG production must be cased with a material that is both strong and functional. The standard establishes requirements for three Product Specification Levels (PSL-1, PSL-2, and PSL-3) and a variety of grades (API 5CT J55, K55, N80, L80, P110).

Types of OCTG (Tubing and Casing)

Lining with Casing

Casing refers to the external tubes. Casing completely surrounds the wellbore, protecting the soil layers and, most importantly, the groundwater from contamination by drilling mud and/or frac fluids. Additionally, it stabilizes the wellbore, which means that the casing must be able to withstand extremely high loads. Drilling and casing operations alternate – the drill string is removed at predetermined intervals and the wellbore is lined and cemented with casing. Then the drilling resumes.

Production with Tubing

Tubing is used to carry petroleum from the well’s depths to the surface – this is the third phase of the wellbore. Oil and gas occasionally self-elevate to the surface; however, pumps are typically required to bring the fluids to the surface.

Besides the 4 1/2-inch diameter, tubing is normally smaller in diameter than casing. A casing or tubing with an outer diameter of 114.3 mm (4 1/2 inches) is considered a threshold size. Anything smaller than tubing is referred to as tubing, while anything larger is referred to as casing.

The casing shrinks in diameter as it descends from the surface to the bottom of the well – there are various types of casing depending on their purpose and diameter. The “kickoff point” is the gradual transition of the wellbore from vertical to horizontal. Horizontal drilling enables more precise targeting of deposits. At the conclusion of the procedure, the drill string is removed and the production casing is inserted and cemented into the wellbore. After fractureing the well, the tubing is installed inside the production casing.

Dimensions and Sizes of OCTG (Tubing and Casing)

- Specification & Size of Tubing

DN	O. D.		Weight		W. T.		End Processing
	O. D.		Non-upset coupling-thread	Upset coupling-thread	W. T.		Steel Grade
	in	mm	lb./ft.	lb./ft.	in	mm	H40	J55	L80	N80	C90	T95	P110
2-3/8	2.375	60.32	4.00	–	0.167	4.24	PU	PN	PN	PN	PN	PN	–
			4.60	4.70	0.190	4.83	PNU	PNU	PNU	PNU	PNU	PNU	PNU
			5.80	5.95	0.254	6.45	–	–	PNU	PNU	PNU	PNU	PNU
			6.60	–	0.295	7.49	–	–	P	–	P	P	–
			7.35	7.45	0.336	8.53	–	–	PU	–	PU	PU	–
2-7/8	2.875	73.02	6.40	6.50	0.217	5.51	PNU	PNU	–	–	–	–	–
			7.80	7.90	0.276	7.01	–	–	–	–	–	–	–
			8.60	8.70	0.308	7.82	–	–	PLB	PLB	PLBE	–	PLB
			9.35	9.45	0.340	8.64	–	–	PLB	PLB	PLBE	–	PLB
			10.50	–	0.392	9.96	–	–	PLB	PLB	PLB	–	PLB
			11.50	–	0.440	11.18	–	–	–	–	PLB	–
3-1/2	3.500	88.90	7.70	–	0.216	5.49	PN	PN	PN	PN	PN	PN	–
			9.20	9.30	0.254	6.45	PNU	PNU	PNU	PNU	PNU	PNU	PNU
			10.20	–	0.289	7.34	PN	PN	PN	PN	PN	PN	–
			12.70	12.95	0.375	9.52	–	–	PNU	PNU	PNU	PNU	PNU
			14.30	–	0.430	10.92	–	–	P	–	P	P	–
			15.50	–	0.476	12.09	–	–	P	–	P	P	–
			17.00	–	0.530	13.46	–	–	P	–	P	P	–
4	4.000	101.60	9.50	–	0.226	5.74	PN	PN	PN	PN	PN	PN	–
			–	11.00	0.262	6.65	PU	PU	PU	PU	PU	PU	–
			13.20	–	0.330	8.38	–	–	P	–	P	P	–
			16.10	–	0.415	10.54	–	–	P	–	P	P	–
			18.90	–	0.500	12.70	–	–	P	–	P	P	–
			22.20	–	0.610	15.49	–	–	P	–	P	P	–
4-1/2	4.500	114.30	12.60	12.75	0.271	6.88	PNU	PNU	PNU	PNU	PNU	PNU	–
			15.20	–	0.337	8.56	–	–	P	–	P	P	–
			17.00	–	0.380	9.65	–	–	P	–	P	P	–
			18.90	–	0.430	10.92	–	–	P	–	P	P	PLB
			21.50	–	0.500	12.70	–	–	P	–	P	P	PLB
			23.70	–	0.560	14.22	–	–	P	–	P	P	PLB
			26.10	–	0.630	16.00	–	–	P	–	P	P	PLB
P——Plain；N—— Non-upset coupling-thread；U—— Upset coupling-thread； L——Integral

- Specification & Size of Casing

DN	O. D.		Weight		W. T.		End Machining Form
	O. D.		Weight		W. T.		Steel Grade
	in	mm	lb/ft	kg/m	in	mm	H40	J55	L80	N80	C90	P110
	in	mm	lb/ft	kg/m	in	mm	H40	K55	L80	N80	T95	P110
4-1/2	4.500	114.3	9.50	14.14	0.205	5.21	PS	PS	–	–	–	–
			10.50	15.63	0.224	5.69	–	PSB	–	–	–	–
			11.60	17.26	0.250	6.35	–	PSLB	PLB	PLB	PLB	PLB
			13.50	20.09	0.290	7.37	–	–	PLB	PLB	PLB	PLB
			15.10	22.47	0.337	9.56	–	–	–	–	–	PLB
5	5.000	127	11.50	17.11	0.220	5.59	–	PS	–	–	–	–
			13.00	19.35	0.253	6.43	–	PSLB	–	–	–	–
			15.00	22.32	0.296	7.52	–	PSLB	PLB	PLB	PLBE	PLB
			18.00	26.79	0.362	9.19	–	–	PLB	PLB	PLBE	PLB
			21.40	31.85	0.437	11.10	–	–	PLB	PLB	PLB	PLB
			23.20	34.53	0.478	12.14	–	–	–	–	PLB	–
			24.10	35.86	0.500	12.70	–	–	–	–	PLB	–
5-1/2	5.500	139.7	14.00	20.83	0.244	6.20	PS	PS	–	–	–	–
			15.50	23.07	0.275	6.98	–	PSLB	–	–	–	–
			17.00	25.30	0.304	7.72	–	PSLB	PLB	PLB	PLBE	PLB
			20.00	29.76	0.361	9.17	–	–	PLB	PLB	PLBE	PLB
			23.00	34.23	0.415	10.54	–	–	PLB	PLB	PLBE	PLB
			26.80	39.88	0.500	12.70	–	–	–	–	–	–
			29.70	44.20	0.562	14.27	–	–	–	–	–	–
			32.60	48.51	0.625	15.88	–	–	–	–	–	–
			35.30	52.53	0.687	17.45	–	–	–	–	–	–
			38.00	56.55	0.750	19.05	–	–	–	–	–	–
			40.50	60.27	0.812	20.62	–	–	–	–	–	–
			43.10	64.14	0.875	22.22	–	–	–	–	–	–
6-5/8	6.625	168.28	20.00	29.76	0.288	7.32	PS	PSLB	–	–	–	–
			24.00	35.72	0.352	8.94	–	PSLB	PLB	PLB	PLBE	PLB
			28.00	41.67	0.417	10.59	–	–	PLB	PLB	PLBE	PLB
			32.00	47.62	0.475	12.06	–	–	PLB	PLB	PLBE	PLB
7	7.000	177.8	17.00	25.30	0.231	5.87	PS	–	–	–	–	–
			20.00	29.76	0.272	6.91	PS	PS	–	–	–	–
			23.00	34.23	0.317	8.05	–	PSLB	PLB	PLB	PLBE	–
			26.00	38.69	0.362	9.19	–	PSLB	PLB	PLB	PLBE	PLB
			29.00	43.16	0.408	10.36	–	–	PLB	PLB	PLBE	PLB
			32.00	47.62	0.453	11.51	–	–	PLB	PLB	PLBE	PLB
			35.00	52.09	0.498	12.65	–	–	PLB	PLB	PLBE	PLB
			38.00	56.55	0.540	13.72	–	–	PLB	PLB	PLBE	PLB
			42.70	63.54	0.625	15.88	–	–	–	–	–	–
			46.40	69.05	0.687	17.45	–	–	–	–	–	–
			50.10	74.56	0.750	19.05	–	–	–	–	–	–
			53.60	79.77	0.812	20.62	–	–	–	–	–	–
			57.10	84.97	0.875	22.22	–	–	–	–	–	–
7-5/8	7.625	193.68	24.00	35.72	0.300	7.62	PS	–	–	–	–	–
			26.40	39.29	0.328	8.33	–	PSLB	PLB	PLB	PLBE	PLB
			29.70	44.20	0.375	9.52	–	–	PLB	PLB	PLBE	PLB
			33.70	50.15	0.430	10.92	–	–	PLB	PLB	PLBE	PLB
			39.00	58.05	0.500	12.70	–	–	PLB	PLB	PLBE	PLB
			42.80	63.69	0.562	14.27	–	–	PLB	PLB	PLB	PLB
			45.30	67.41	0.595	15.11	–	–	PLB	PLB	PLB	PLB
			47.10	70.09	0.625	15.88	–	–	PLB	PLB	PLB	PLB
			51.20	76.19	0.687	17.45	–	–	–	–	–	–
			55.30	80.30	0.750	19.05	–	–	–	–	–	–
8-5/8	8.625	219.08	24.00	35.72	0.264	6.71	–	PS	–	–	–	–
			28.00	41.62	0.304	7.72	PS	–	–	–	–	–
			32.00	47.62	0.352	8.94	PS	PSLB	–	–	–	–
			36.00	53.57	0.400	10.16	–	PSLB	PLB	PLB	PLBE	PLB
			40.00	59.53	0.450	11.43	–	–	PLB	PLB	PLBE	PLB
			44.00	65.48	0.500	12.70	–	–	PLB	PLB	PLBE	PLB
			49.00	72.92	0.557	14.15	–	–	PLB	PLB	PLBE	PLB
9-5/8	9.625	244.48	32.30	48.07	0.312	7.92	PS	–	–	–	–	–
			36.00	53.57	0.352	8.94	PS	PSLB	–	–	–	–
			40.00	59.53	0.395	10.03	–	PSLB	PLB	PLB	PLBE	–
			43.50	64.73	0.435	11.05	–	–	PLB	PLB	PLBE	PLB
			47.00	69.94	0.472	11.99	–	–	PLB	PLB	PLBE	PLB
			53.50	79.62	0.545	13.84	–	–	PLB	PLB	PLBE	PLB
			58.40	86.91	0.595	15.11	–	–	PLB	PLB	PLB	PLB
			59.40	88.40	0.609	15.47	–	–	–	–	–	–
			64.90	96.58	0.672	17.07	–	–	–	–	–	–
			70.30	104.62	0.734	18.64	–	–	–	–	–	–
			75.60	112.50	0.797	20.24	–	–	–	–	–	–
10-3/4	10.750	273.05	32.75	48.74	0.279	7.09	PS	–	–	–	–	–
			40.50	60.27	0.350	8.89	PS	PSB	–	–	–	–
			15.50	67.71	0.400	10.16	–	PSB	–	–	–	–
			51.00	75.90	0.450	11.43	–	PSB	PSB	PSB	PSBE	PSB
			55.50	82.59	0.495	12.57	–	–	PSB	PSB	PSBE	PSB
			60.70	90.33	0.545	13.84	–	–	–	–	PSBE	PSB
			65.70	97.77	0.595	15.11	–	–	–	–	PSB	PSB
			73.20	108.93	0.672	17.07	–	–	–	–	–	–
			79.20	117.86	0.734	18.64	–	–	–	–	–	–
			85.30	126.94	0.797	20.24	–	–	–	–	–	–
11-3/4	11.750		42.00	62.50	0.333	8.46	PS	–	–	–	–	–
			47.00	69.94	0.375	20.24	–	–	–	–	–	–
			54.00	80.36	0.435	8.46	–	–	–	–	–	–
			60.00	89.29	0.489	9.53	–	–	–	–	–	–
			65.00	96.73	0.534	11.05	–	–	–	–	–	–
			71.00	105.66	0.582	14.42	–	–	–	–	–	–
13-3/8	13.375	339.73	48.00	71.43	0.330	8.38	PS	–	–	–	–	–
			54.50	81.10	0.380	9.65	–	PSB	–	–	–	–
			61.00	90.78	0.430	10.92	–	PSB	–	–	–	–
			68.00	101.19	0.480	12.19	–	PSB	PSB	PSB	PSB	PSB
			72.00	107.15	0.514	13.06	–	–	PSB	PSB	PSB	PSB
16	16.000	406.4	65.00	96.73	0.375	9.53	PS	–	–	–	–	–
			75.00	111.61	0.438	11.13	–	PSB	–	–	–	–
			84.00	125.01	0.495	12.57	–	PSB	–	–	–	–
			109.00	162.21	0.656	16.66	–	P	P	P	–	P
18-5/8	18.625	473.08	87.50	130.21	0.435	11.05	PS	PSB	–	–	–	–
20	20.000	508	94.00	139.89	0.438	11.13	PSL	PSLB	–	–	–	–
			106.50	158.49	0.500	12.70	–	PSLB	–	–	–	–
			133.00	197.93	0.635	16.13	–	PSLB	–	–	–	–
P——Plain；S——Short-thread；L——Long-thread；B——Buttress thread；E——Extreme thread

- Chemical Composition of OCTG (Tubing and Casing)

Group	Steel Grade	Type	C		Mn		Mo		Cr		Ni	Cu	P	S	Si
Group	Steel Grade	Type	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	max.	max.	max.
1	H40	–	–	–	–	–	–	–	–	–	–	–	0.03	0.03	–
	J55	–	–	–	–	–	–	–	–	–	–	–	0.03	0.03	–
	K55	–	–	–	–	–	–	–	–	–	–	–	0.03	0.03	–
	N80	1	–	–	–	–	–	–	–	–	–	–	0.03	0.03	–
	N80	Q	–	–	–	–	–	–	–	–	–	–	0.03	0.03	–
2	M65	–	–	–	–	–	–	–	–	–	–	–	0.03	0.03	–
	L80	1	–	0.43	–	1.9	–	–	–	–	0.25	0.35	0.03	0.03	0.5
		9Cr	–	0.15	0.3	0.6	0.9	1.1	8	10	0.5	0.25	0.02	0.01	1.0
		13Cr	0.15	0.22	0.25	1	–	–	12	14	0.5	0.25	0.02	0.01	1.0
	C90	1	–	0.35	–	1.2	0.25	0.85	–	1.5	0.99	–	0.02	0.01	–
	C90	2	–	0.5	–	1.9	–	NL	–	NL	0.99	–	0.03	0.01	–
	C95	–	–	0.45	–	1.9	–	–	–	–	–	–	0.03	0.03	0.5
	T95	1	–	0.35	–	1.2	0.25	0.85	0.4	1.5	0.99	–	0.02	0.01	–
	T95	2	–	0.5	–	1.9	–	–	–	–	0.99	–	0.03	0.01	–
3	P110	–	–	–	–	–	–	–	–	–	–	–	0.03	0.03	–
4	Q125	1	–	0.35	–	1.35	–	0.85	–	1.5	0.99	–	0.02	0.01	–
		2	–	0.35	–	1	–	NL	–	NL	0.99	–	0.02	0.02	–
		3	–	0.5	–	1.9	–	NL	–	NL	0.99	–	0.03	0.01	–
		4	–	0.5	–	1.9	–	NL	–	NL	0.99	–	0.03	0.02	–
a. The carbon content for L80 may be increased up to 0, 50 % maximum if the product is oil-quenched. b. The molybdenum content for Grade C90 Type 1 has no minimum tolerance if the WT is less than 17, 78 mm. c. The carbon content for R95 may be increased up to 0, 55 % maximum if the product is oil-quenched. d. The molybdenum content for T95 Type 1 may be decreased to 0, 15 % minimum if the WT is less than 17, 78 mm. e. For EW Grade P110, the phosphorus content shall be 0,020 % maximum and the sulfur content 0,010 % maximum NL = no limit. Elements shown shall be reported in product analysis.

- Mechanical Properties Tensile Strength and Yield Strength of OCTG (Tubing and Casing)

Group	Steel Grade	Type	Total %	Yield Strength MPa		Tensile MPa	Hardness max		W. T. mm	Changes in Hardness
Group	Steel Grade	Type	Total %	min.	max.	min.	HRC	HBW	W. T. mm	Changes in Hardness
1	H40	–	0.5	276	552	414	–	–	–	–
	J55	–		379	552	517	–	–	–	–
	K55	–		379	552	655	–	–	–	–
	N80	1		552	758	689	–	–	–	–
	N80	Q		552	758	689	–	–	–	–
2	M65	–	0.5	448	586	586	22	235	–	–
	L80	1		552	655	655	23	241	–	–
		9Cr		552	655	655	23	241	–	–
		13Cr		552	655	655	23	241	–	–
	C90	1、2		621	724	689	25.4	255	≤ 12.70	3.0
				621	724	689	25.4	255	12.71 ~ 19.04	4.0
				621	724	689	25.4	255	19.05 ~ 25.39	5.0
				621	724	689	25.4	255	≥25.40	6.0
	C95	–		655	758	724	–	–	–	–
	T95	1、2		655	758	724	25.4	255	≤ 12.70	3.0
				655	758	724	25.4	255	12.71 ~ 19.04	4.0
				655	758	724	25.4	255	19.05 ~ 25.39	5.0
				655	758	724	25.4	255	≥25.40	6.0
3	P110	–	0.6	758	965	862	–	–	–	–
4	Q125	all	0.65	862	1034	931	–	–	≤ 12.70	3.0
				862	1034	931	–	–	12.71 ~ 19.04	4.0
				862	1034	931	–	–	≥19.05	5.0

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