OCTG (Oil Country Tubular Goods) Tubing is a critical component used to extract oil and gas from the wellbore to the surface. Manufactured strictly in accordance with API Spec 5CT, our tubing pipes are designed to withstand extreme internal pressures, tensile loads, and corrosive environments.

Unlike casing, which lines the wellbore, tubing is the conduit for production. Our tubing is available with standard API connections (NU, EU, IJ) and premium connections, along with end-upsetting (External Upset or Integral) to ensure maximum joint strength and reliable performance during production operations.

Thread Connections & Upsetting

Tubing connections are crucial for production safety. We offer the following standard connections, fully compliant with API SPEC 5B:

NU (Non-Upset Tubing): The pipe body has a uniform outside diameter; the coupling is the same outside diameter as the pipe. Suitable for general service.

EU (External Upset Tubing): The pipe ends are thickened externally to provide greater joint strength, ideal for deeper wells.

IJ (Integral Joint Tubing): The thread is machined directly onto the thickened pipe body without a separate coupling, ensuring excellent gas-tightness and simplifying handling.

Premium Connections: Available upon request for HPHT and highly corrosive environments.

Dimension of OCTG Tubing

Group	Grade	Type	Total elongation under load %	Yield strength Mpa		Tensile strength min MPa	Hardness max
Group	Grade	Type	Total elongation under load %	min	max	Tensile strength min MPa	HRC	HBW
1	2	3	4	5	6	7	8	9
1	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	-	-
2	L80	1	0.5	552	655	655	23	241
	L80	9Cr	0.5	552	655	655	23	241
	L80	13Cr	0.5	552	655	655	23	241
	C90		0.5	621	724	689	25.4	255
	C95	-	0.5	655	758	724	-	-
	T95		0.5	655	758	724	25.4	255
3	P110	-	0.6	758	965	862	-	-
4	Q125	All	0.65	862	1034	931	-	-

Mechanical Properties of OCTG Tubing

Label				D Outside diameter mm	Wall thickness t mm	C Type of end-finish
1	2					H40	J55	L80	N80 1Q	C90	T95	P110
1	NU T&C	EU T&C	IJ			H40	J55	L80	N80 1Q	C90	T95	P110
1	2	3	4	5	9	10	11	12	13	14	15	16
1.9	2.75	2.9	2.76	48.26	3.68	PNUI	PNUI	PNUI	PNUI	PNUI	PNUI	-
1.9	3.65	3.73	-	48.26	5.08	PU	PU	PU	PU	PU	PU	PU
1.9	4.42	-	-	48.26	6.35	-	-	P	-	P	P	-
2.375	4	-	-	60.32	4.24	PU	PN	PN	PN	PN	PN	-
2.375	4.6	4.7	-	60.32	4.83	PNU	PNU	PNU	PNU	PNU	PNU	PNU
2.375	5.8	5.95	-	60.32	6.45	-	-	PNU	PNU	PNU	PNU	PNU
2.375	6.6	-	-	60.32	7.49	-	-	P	-	P	P	-
2.375	7.35	7.45	-	60.32	8.53	-	-	PU	-	PU	PU	-
2.875	6.4	6.5	-	73.02	5.51	PNU	PNU	PNU	PNU	PNU	PNU	PNU
2.875	7.8	7.9	-	73.02	7.01	-	-	PNU	PNU	PNU	PNU	PNU
2.875	8.6	8.7	-	73.02	7.82	-	-	PNU	PNU	PNU	PNU	PNU
2.875	9.35	9.45	-	73.02	8.64	-	-	PU	-	PU	PU	-
2.875	10.5	-	-	73.02	9.96	-	-	P	-	P	P	-
3.5	7.7	-	-	88.9	5.49	PN	PN	PN	PN	PN	PN	-
3.5	9.2	9.3	-	88.9	6.45	PNU	PNU	PNU	PNU	PNU	PNU	PNU
3.5	10.2	-	-	88.9	7.34	PN	PN	PN	PN	PN	PN	-
3.5	12.7	12.95	-	88.9	9.52	-	-	PNU	PNU	PNU	PNU	PNU
3.5	14.3	-	-	88.9	10.92	-	-	P	-	P	P	-
3.5	15.5	-	-	88.9	12.09	-	-	P	-	P	P	-
4	9.5	-	-	101.6	5.74	PN	PN	PN	PN	PN	PN	-
4	10.7	11	-	101.6	6.65	PU	PU	PU	PU	PU	PU	-
4	13.2	-	-	101.6	8.38	-	-	P	-	P	P	-
4	16.1	-	-	101.6	10.54	-	-	P	-	P	P	-
4.5	12.6	12.75	-	114.3	6.88	PNU	PNU	PNU	PNU	PNU	PNU	-
4.5	15.2	-	-	114.3	8.56	-	-	P	-	P	P

Steel Grades & Applications

We supply a comprehensive range of API 5CT steel grades to meet various downhole conditions:

J55 & K55: Standard strength grades for shallow to medium-depth production.

N80 (Type 1 & Q): Higher strength grades for deeper wells and higher pressure production.

L80 (Type 1): Used in environments requiring resistance to sulfide stress cracking (H2S) in sour service.

L80-9Cr & L80-13Cr: High-alloy grades offering excellent resistance to carbon dioxide (CO2) and chloride corrosion in sweet wells.

C90, T95 & P110: High-strength grades designed for deep, high-pressure, and high-temperature (HPHT) wells.

Specification of OCTG Tubing

The most common API tubing specifications are listed here. Others steel grades, nominal weights, and connections are available on request.

Label				OD (mm)	WT (mm)	Type of End-finish
	NU T&C	EU T&C	IJ	OD (mm)	WT (mm)	H40	J55	L80	N80	C90	T95	P110
1.9	2.75	2.9	2.76	48.26	3.68	PNUI	PNUI	PNUI	PNUI	PNUI	PNUI	-
1.9	3.65	3.73	-	48.26	5.08	PU	PU	PU	PU	PU	PU	PU
1.9	4.42	-	-	48.26	6.35	-	-	P	-	P	P	-
2 3/8	4	-	-	60.32	4.24	PU	PN	PN	PN	PN	PN	-
2 3/8	4.6	4.7	-	60.32	4.83	PNU	PNU	PNU	PNU	PNU	PNU	PNU
2 3/8	5.8	5.95	-	60.32	6.45	-	-	PNU	PNU	PNU	PNU	PNU
2 3/8	6.6	-	-	60.32	7.49	-	-	P	-	P	P	-
2 3/8	7.35	7.45	-	60.32	8.53	-	-	PU	-	PU	PU	-
2 7/8	6.4	6.5	-	73.02	5.51	PNU	PNU	PNU	PNU	PNU	PNU	PNU
2 7/8	7.8	7.9	-	73.02	7.01	-	-	PNU	PNU	PNU	PNU	PNU
2 7/8	8.6	8.7	-	73.02	7.82	-	-	PNU	PNU	PNU	PNU	PNU
2 7/8	9.35	9.45	-	73.02	8.64	-	-	PU	-	PU	PU	-
2 7/8	10.5	-	-	73.02	9.96	-	-	P	-	P	P	-
3 1/2	7.7	-	-	88.9	5.49	PN	PN	PN	PN	PN	PN	-
3 1/2	9.2	9.3	-	88.9	6.45	PNU	PNU	PNU	PNU	PNU	PNU	PNU
3 1/2	10.2	-	-	88.9	7.34	PN	PN	PN	PN	PN	PN	-
3 1/2	12.7	12.95	-	88.9	9.52	-	-	PNU	PNU	PNU	PNU	PNU
3 1/2	14.3	-	-	88.9	10.92	-	-	P	-	P	P	-
3 1/2	15.5	-	-	88.9	12.09	-	-	P	-	P	P	-
4	9.5	-	-	101.6	5.74	PN	PN	PN	PN	PN	PN	-
4	10.7	11	-	101.6	6.65	PU	PU	PU	PU	PU	PU	-
4	13.2	-	-	101.6	8.38	-	-	P	-	P	P	-
4	16.1	-	-	101.6	10.54	-	-	P	-	P	P	-
4 1/2	12.6	12.75	-	114.3	6.88	PNU	PNU	PNU	PNU	PNU	PNU	-
4 1/2	15.2	-	-	114.3	8.56	-	-	P	-	P	P	-

Manufacturing Process of OCTG Tubing

Manufacturing Process of OCTG Tubing

Packing of OCTG Tubing

Packing of OCTG Tubing

Q1: What is the difference between OCTG Casing and Tubing?
A: Casing is the large-diameter pipe permanently installed in the wellbore to line the walls and prevent collapse. Tubing is the smaller-diameter pipe run inside the casing to transport the produced oil and gas to the surface. Tubing can be pulled out for maintenance or replacement.

Q2: What is the difference between NU, EU, and IJ connections?
A:NU (Non-Upset): Standard pipe body, the connection strength is limited.

EU (External Upset): The pipe ends are thickened externally, providing higher joint strength than NU, making it suitable for deeper wells.

IJ (Integral Joint): No coupling is used; the thread is cut directly into the thickened pipe ends. It offers excellent gas-tightness and is easier to run in and out of the well.

Q3: Why is Upsetting (加厚) important for tubing?

A: The tubing string is subjected to massive tensile loads from its own weight. Upsetting thickens the pipe ends, allowing for a stronger thread connection so the tubing doesn't break under its own weight in deep wells.

Q4: How do you ensure the quality of the threads?
A: We maintain Strict Quality Control on threading. Every pipe end undergoes rigorous API thread gauging (using API ring and plug gauges), visual inspection, and phosphating treatment. We fully accept third-party inspections (such as SGS, BV) to verify thread dimensions.

Q5: Do you provide Drift Testing?

A: Yes. Every tubing pipe undergoes a Drift Test to ensure the internal bore is perfectly clear and uniform, guaranteeing that wireline tools and downhole equipment can pass through smoothly during production.

Q6: What are your payment terms and lead times?
A: We offer Flexible Payment plans, including L/C (Letter of Credit) and open account. Standard lead times are typically 20–35 days after receipt of the advance payment, depending on the steel grade, thread type, and order volume.

Tubing

Dimension of OCTG Tubing

Mechanical Properties of OCTG Tubing

Steel Grades & Applications

Related Products

Contact Us

Product

Quick Links