What is Sour Service Steel Pipe?

Date:2024-10-28Tags:Sour Service Steel Pipe, seamless pipes , welded pipes

What is Sour Service Steel Pipe?

Sour service steel pipes are suitable for pipelines in corrosive environments.

In practical applications, sour service pipes are mainly used in H2S-containing environments in the oil and gas industry. Usually, these pipes need to meet standards such as API Spec 5L and comply with specifications such as NACE MR0175/ISO 15156 to ensure their safety performance in sour environments. According to international regulations, when the partial pressure of H2S in the pipeline reaches 300 Pa (Pa), the bridge used must have the ability to resist acid corrosion. These sour service pipes often use treated specific low-alloy steel or stainless steel, which can effectively inhibit acid corrosion phenomena such as activated corrosion cracking (SCC).
As we all know, the corrosion of pipelines is an important factor affecting their safe use and service life. Severe corrosion will cause leakage of oil and gas pipelines, and even cause explosions in severe cases. Pipeline corrosion poses a huge threat to personal safety and environmental pollution, so the production of sour pipelines is of great significance. At present, the manufacturing inspection standards for sour pipelines are mainly based on API Spec 5L.

Sour service pipeline definition

Sour oil pipelines are mainly used in H2S environment, which is a harmful chemical and is very prone to corrosion. According to international regulations: when the H2S partial pressure reaches 300pa, the pipeline pipe used should have acid corrosion resistance. Sour service pipelines include NACE pipes.

Pipes can be seamless pipes or welded pipes. Sour drill pipe is a special pipe used in drilling applications. The drilling environment is harsh and the risk of exposure to H2S is high. Hydrogen induced cracking may occur in sour environments. Sour service line pipe reduces HIC and provides better mechanical properties for the pipeline. The yield strength of the pipe ranges from 245MPa to 635MPa, depending on the pipe grade, and the tensile strength ranges from 415MPa to 760MPa. These are essentially carbon steel pipes that have been modified to adapt to sour service.

How sour pipes are made?

In API Spec 5L, the pipeline steel used for sour service pipelines is pure fully killed steel. (For ordinary pipeline pipes, the steel is grain-killed steel)
It should be noted that the high purity of the steel can ensure a low content of impurities such as S and P.

In addition, it is also required to formulate control and inspection standards for the shape of inclusions in acid service pipeline steel. Because hydrogen-induced cracking caused by inclusions must first be determined from its morphology.

In addition, since pipeline steel production generally adopts controlled rolling process, inclusions are deformed during rolling and are linear or long strips along the rolling direction, resulting in anisotropy of pipeline steel. Therefore, in order to improve the corrosion resistance of pipeline steel, the inclusion morphology must be controlled.

seamless pipes


Material Specification Chart Sour Service Pipe

No. Grade Specification Executive Standard
Outer Diameter /mm Wall Thickness /mm Economical Length/m
1 BNS PSL2
X42NS PSL2
X46NS PSL2
X52NS PSL2
10 ~ 127 1 ~ 20 6 ~ 12.0 API 5L Line Pipe Standard
42 ~ 114.3 3.5 ~ 8 6 ~ 12.2
60 ~ 114.3 8 ~ 12 6 ~ 12.2
114.3 ~ 180 3.8 ~ 14 6 ~ 12.2
114.3 ~ 180 14 ~ 22 6 ~ 12.2
68 ~ 232 10 ~ 20 6 ~ 12.2
76 ~ 254 20 ~ 55 6 ~ 12.2
140 ~ 368 6 ~ 14 6 ~ 12.2
140 ~ 368 14 ~ 42 6 ~ 12.2
318 ~ 720 14 ~ 120 4 ~ 12.5
2 BQS PSL2
X42QS PSL2
42 ~ 114.3 3.5 ~ 12 6 ~ 12.2
114.3 ~ 180 3.8 ~ 22 6 ~ 12.2
68 ~ 254 10 ~ 30 6 ~ 12.2
140 ~ 368 6 ~ 30 6 ~ 12.2
318 ~ 720 14 ~ 30 4 ~ 12.5
3 X46QS PSL2
X52QS PSL2
X56QS PSL2
X60QS PSL2
42 ~ 114.3 3.5 ~ 12 6 ~ 12.2
114.3 ~ 180 3.8 ~ 22 6 ~ 12.2
68 ~ 254 10 ~ 30 6 ~ 12.2
140 ~ 368 6 ~ 30 6 ~ 12.2
318 ~ 720 14 ~ 30 4 ~ 12.5
4 X65QS PSL2
X70QS PSL2
42 ~ 114.3 3.5 ~ 12 6 ~ 12.2
114.3 ~ 180 3.8 ~ 22 6 ~ 12.2
68 ~ 254 10 ~ 25 6 ~ 12.2
140 ~ 368 6 ~ 25 6 ~ 12.2
318 ~ 720 14 ~ 25 4 ~ 12.5

Material For Sour Service Pipeline Inspection frequency

Type of inspection Type of pipe Frequency of inspection
Hardness testing of pipe with
D < 508 mm (20.000 in)
SMLS,HFW, SAWL, or SAWH Once per test unit of not more than 100 lengths of pipe with the same cold-expansion ratio a
Hardness testing of pipe with
D ≥ 508 mm (20.000 in)
SMLS,HFW, SAWL, or SAWH Once per test unit of not more than 50 lengths of pipe with the same cold-expansion ratio a
Hardness testing of hard spots in welded pipe HFW, SAWL, or SAWH Each hard spot found on the internal or external surface of the pipe
if agreed, hardness testing of the longitudinal or helical-seam weld of welded pipe HFW, SAWL, or SAWH As specified in the purchase order
pipe diameter and out-of-roundness for pipe with
D ≤ 168,3 mm (6.625 in)
SMLS,HFW, SAWL, or SAWH Once per test unit of not more than 100 lengths of pipe
pipe diameter and out-of-roundness for pipe with
D> 168,3 mm (6.625 in)
SMLS,HFW, SAWL, or SAWH Once per test unit of not more than 20 lengths of pipe
Non-destructive inspection SMLS,HFW, SAWL, or SAWH In accordance with Annex K
HIC test SMLS,HFW, SAWL, or SAWH One test for each of the first three heats applied; thereafter, one test for each test unit of not more than ten heats of steel
if agreed, SSC test SMLS,HFW, SAWL, or SAWH One test for each pipe provided for manufacturing procedure qualification

Chemical Formula Of Sour Service Drill Pipe

Steel grade Mass fraction, based upon heat and product analyses
%
maximum
Carbon
equivalent a

%
maximum
C b Si Mn b P S V Nb Ti Other c, d CE llw CE pcm
SMLS and welded pipes
L245NS or BNS 0,14 0,40 1,35 0,020 0,003 e f f 0,04 g 0,36 0,19 h
L290NS or X42NS o,14 0,40 1,35 0,020 0,003 e 0,05 0,05 0,04 - 0,36 0,19 h
L320NS or X46NS 0,14 0,40 1,40 0,020 0,003 e 0,07 0,05 0,04 g 0,38 0,20 h
L360NS or X52NS 0,16 0,45 1,65 0,020 0,003 e 0,10 0,05 0,04 g 0,43 0,22 h
L245QS or BQS 0,14 0,40 1,35 0,020 0,003 e 0,04 0,04 0,04 - 0,34 0,19 h
L 290QS or X42QS 0,14 0,40 1,35 0,020 0,003 e 0,04 0,04 0,04 - 0,34 0,19 h
L320QS or X46QS 0,15 0,45 1,40 0,020 0,003 e 0,05 0,05 0,04 - 0,36 0,20 h
L360QS or X52QS 0,16 0,45 1,65 0,020 0,003 e 0,07 0,05 0,04 g 0,39 0,20 h
L390QS or X56QS 0,16 0,45 1,65 0,020 0,003 e 0,07 0,05 0,04 g 0,40 0,21 h
L415QS or X60QS 0,16 0,45 1,65 0,020 0,003 e 0,08 0,05 0,04 g,i,k 0,41 0,22 h
L450QS or X65QS 0,16 0,45 1,65 0,020 0,003 e 0,09 0,05 0,06 g,i,k 0,42 0,22 h
L485QS or X70QS 0,16 0,45 1,65 0,020 0,003 e 0,09 0,05 0,06 g,i,k 0,42 0,22 h
welded pipe
L245MS or BMS 0,10 0,40 1,25 0,020 0,002 e 0,04 0,04 0,04 - - 0,19
L290MS or X42MS 0,10 0,40 1,25 0,020 0,002 e 0,04 0,04 0,04 - - 0,19
L320MS or X46 MS 0,10 0,45 1,35 0,020 0,002 e 0,05 0,05 0,04 - - 0,20
L360MS or X52 MS 0,10 0,45 1,45 0,020 0,002 e 0,05 0,06 0,04 - - 0,20
L390MS or X56 MS 0,10 0,45 1,45 0,020 0,002 e 0,06 0,08 0,04 g - 0,21
L415MS or X60 MS 0,10 0,45 1,45 0,020 0,002 e 0,08 0,08 0,06 g,i - 0,21
L450MS or X65MS 0,10 0,45 1,60 0,020 0,002 e 0,10 0,08 0,06 g,i,j - 0,22
L485MS or X70 MS 0,10 0,45 1,60 0,020 0,002 e 0,10 0,08 0,06 g,i,j - 0

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