Casing Pipe - Knowledge

Types:

Casing Pipe, Oil Well Casing, OCTG Casing & Tubing

Grades of Casing:

API 5CT J55/K55/N80/L80-1/L80-9Cr/L80-13Cr/P110/Q125/K55 D10/L80 D10

Sizes of Casing:

Diameter: from 4 1/2 inch to 20 inch (48.26mm - 508mm)

Nominal Weight: from 9.5 lb/ft to 169 lb/ft

from 9.5 ppf to 169 ppf

Lenght: R1, R2, R3

Types of Casing:

Seamless casing

ERW casing

Casing nipple

Casing coupling

Connection:

BTC, STC, LTC, NUE, EUE

Coating

3PP Coating

3PE Coating

FBE Coating

Epoxy Coating

Special Painting

Applications:

Oil well extracting casing
Borehole casing
Borewell casing

Dimension Tolerance of casing pipe

Types of steel tubes	Outer Diameter		Wall Thickness
Cold-rolled tubes	Tube sizes(mm)	Tolerances(mm)	Tolerances(mm)
	＜114.3	±0.79	－12.5％
	≥114.3	－0.5％,＋1％	－12.5％

Chemical Composition of casing pipe

Standard	Grade	Chemical compositions(％)
API SPEC 5CT	J55	C	Si	Mn	P	S	Cr	Ni	Cu	Mo	V
	K55	0.34～0.39	0.20～0.35	1.25～1.50	≤0.020	≤0.015	≤0.15	≤0.20	≤0.20	/	/
	N80	0.34～0.38	0.20～0.35	1.45～1.70	≤0.020	≤0.015	≤0.15	/	/	/	0.11～0.16
	L80	0.15～0.22	≤1.00	0.25～1.00	≤0.020	≤0.010	12.0～14.0	≤0.20	≤0.20	/	/
	P110	0.26～0.395	0.17～0.37	0.40～0.70	≤0.020	≤0.010	0.80～1.10	≤0.20	≤0.20	0.15～0.25	≤0.08

Mechanical properties of casing pipe

Grade	Type	Total elongation under load (%)	Yield strength (min)	Yield strength (max)	Tensile strength min Mpa	Hardness Max (HRC)	Hardness Max(HBW)
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	-	-
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
P110	-	0.6	758	965	862	-	-
Q125	All	0.65	862	1034	931	-	-

Casing Pipe is used to support the oil, gas wells of steel pipe, in order to ensure the drilling process and the completion of the entire well after the normal operation. Each well has several layers of casing depending on the drilling depth and geology. Casing down to use cement cementing, it and the tubing, drill pipe is different, can not be reused, a one-time consumption of materials. Therefore, the casing of the total consumption of more than 70% of the wells. Casing according to the use can be divided into: catheter, surface casing, casing technology and oil casing.

Tubing Pipe is the conduit through which oil and gas are brought from the producing formations to the field surface facilities for processing. Tubing must be adequately strong to resist loads and deformations associated with production and workovers. Further, tubing must be sized to support the expected rates of production of oil and gas. Clearly, tubing that is too small restricts production and subsequent economic performance of the well. Tubing that is too large, however, may have an economic impact beyond the cost of the tubing string itself, because the tubing size will influence the overall casing design of the well.

API Tubing Pipe Size: API Tubing naturally has a smaller diameter than casing, except for the 4 1/2-inch diameter. An outer diameter of 114.3 mm (4 1/2 inches) is considered a threshold and can be either casing or tubing. Anything smaller is called tubing, anything larger is casing.

Casing Pipe Manufacturing Process:

Steel ingot heating → hydraulic punching → reheating → extension → periodic rolling → reheating → sizing → cooling → straightening → pipe cutting → inspection

1. An annular heating furnace is required for ingot heating;
2. Punching and reheating with hydraulic press;
3. The oil casing plant uses a two-roller guide plate extension machine for extension;
4. Re-use a disc heating furnace for periodic rolling, and use a non-entry furnace for reheating, cooling, straightening, pipe cutting, and inspection.

Pipe Manufacturing Process for Seamless & Welded Pipe