ERW Casing, API Steel Casing Pipe

ERW Casing - Casing made of electric welded pipe as raw material

ERW (Electric Resistance Welded) pipe refers to a straight seam welded pipe made by high-frequency resistance welding. The raw steel plate (steel coil) of ERW welded pipe is low-carbon micro-alloy steel rolled by TMCP (Thermo-Mechanical Control Process).

ERW casing uses hot-rolled coil as raw material. The surface quality of the coil is the surface quality of the ERW casing. The surface quality of the hot-rolled coil is easy to control and has high quality. Therefore, the surface quality of the ERW pipe is much better than that of the seamless pipe.

Oil ERW casing is a large-diameter pipe that serves to fix the wall or borehole of oil and gas wells. The casing is inserted into the wellbore and fixed with cement to help the wellbore separate the rock layer and prevent the wellbore from collapsing, while ensuring the circulation of drilling mud for drilling and production.

Different types of ERW casing used in the oil production process:
Surface oil casing: protects the drilling well from pollution by shallow water and shallow gas layers, supports wellhead equipment and maintains the weight of other layers of the casing.
Technical oil casing: separates the pressure of different layers so that the drilling fluid can circulate normally and protect the production casing, and installs anti-burst devices, leak-proof devices and tail pipes in the drilling well.
Reservoir oil casing: guides oil and gas out of the reservoir layer below the surface. Used to protect the drilling well and stratify the drilling mud. When oil casing is produced, the outer diameter is usually 114.3 mm to 508 mm.

Features of ERW Casing:

1. ERW pipe has high dimensional accuracy, good surface quality, uniform wall thickness, and high casing extrusion resistance;
Compared with similar API seamless casing, ERW casing has 30%-40% higher extrusion strength and about 50% higher explosion resistance (internal pressure).
2. ERW pipe parent material has few impurities, uniform structure, good material toughness, and high casing toughness, which can meet the needs of special well conditions in oil fields;
3. ERW pipe has a large diameter span, and compared with seamless casing, it has certain economic advantages in large diameter (above 219mm) specifications.

4. ERW pipe has low cost. Compared with similar seamless casing, ERW casing has 5%-10% lower cost, high production efficiency, high degree of mechanization and automation, and low production energy consumption. The yield rate of ERW casing is 93%-98%, while the yield rate of seamless casing is 85%-90%; the investment of the entire project is also 40% lower than that of seamless casing.
5. ERW pipe production technology is advanced and product quality control is good. The base material of ERW casing is controlled rolled coil, which is isotropic and can be 100% non-destructively tested. Its production process includes strict welding parameter control to ensure product quality.
6. The weld toughness of ERW pipe is good. The manufacturing process of ERW casing can ensure high-strength and high-toughness welds. The composition structure of the weld and the C, S and P content in the matrix material are low, which makes the casing tougher.

ERW Casing Specification:

Outside Diameter		Nominal Weight		Wall Thickness		Grade	Connection Type*
in.	mm	lb/ft	kg/m	in.	mm
5-1/2	139.70	14.00	20.83	0.244	6.20	J55/K55	PS
		15.50	23.07	0.275	6.98	J55/K55	PSLB
		17.00	25.30	0.304	7.72	J55/K55	PSLB
6-5/8	168.28	24.00	35.72	0.352	8.94	J55/K55	PSLB
7	177.80	20.00	29.76	0.272	6.91	J55/K55	PS
		23.00	34.23	0.317	8.05	J55/K55	PSLB
		26.00	38.69	0.362	9.19	J55/K55	PSLB
8-5/8	219.08	24.00	35.75	0.264	6.71	J55/K55	PS
		28.00	41.67	0.304	7.72	J55/K55	PS
		32.00	47.66	0.352	8.94	J55/K55	PSLB
		36.00	53.62	0.400	10.16	J55/K55	PSLB
9-5/8	244.48	36.00	53.57	0.352	8.94	J55/K55	PSLB
		40.00	59.53	0.395	10.03	J55/K55	PSLB
10-3/4	273.05	40.50	60.32	0.350	8.89	J55/K55	PSB
		45.50	67.78	0.400	10.16	J55/K55	PSB
13-3/8	339.70	48.00	71.43	0.330	8.38	J55/K55	PSB
		54.50	81.18	0.380	9.65	J55/K55	PSB
		61.00	90.86	0.430	10.92	J55/K55	PSB
		68.00	101.29	0.480	12.19	J55/K55	PSB

* P - plain end, S - short round thread, B - butress, L - long round thread.

Read more: Seamless casing vs. ERW casing or ERW Steel Pipe Manufacturing Process