Petroleum and natural gas industries - OCTG used for special environment .Part 1: Recommended practice on selection of casing and tubing ofcarbon and low alloy steels for use in sour service
SY/T 6857.1-2024 Petroleum and natural gas industries - OCTG used for special environment .Part 1: Recommended practice on selection of casing and tubing ofcarbon and low alloy steels for use in sour service English, Anglais, Englisch, Inglés, えいご
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ICS
E
Professional standard of the People's Republic of China
SY/T 6857.1-2024
Replaces SY/T 6857.1-2012
Petroleum and natural gas industries OCTG used for special environment - Part 1: Recommended practice on selection of casing and tubing of carbon and low alloy steels for use in sour service
石油天然气工业特殊环境用油井管第1部分：含H2S油气田环境下 碳钢和低合金钢油管和套管选用推荐做法
(English Translation)
Issue date: 2024-12-25 Implementation date: 2025-06-25
Issued by National Development and Reform Commission, P.R.C
Contents
Foreword
Introduction
1 Scope
2 Normative References
3 Terms, Definitions, and Abbreviated Terms
3.1 Terms and Definitions
3.2 Abbreviated Terms
4 Corrosion Service Conditions and Assessment
4.1 General Requirements
4.2 Factors Influencing Corrosion
4.3 Assessment of Corrosion Service Conditions
5 Selection Principles for Tubing and Casing
5.1 Analysis of Service Conditions
5.2 Corrosion Types and Control Targets for Corrosion Severity
5.3 Product Quality Control
5.4 Selection of Products Covered by GB/T 19830
5.5 Selection of Products Not Covered by GB/T 19830
5.6 Selection of Products with Special Threads Not Covered by GB/T 9253
6 Quality Control for Tubing and Casing Products Not Covered by GB/T 19830
6.1 General
6.2 Manufacturing Process
6.3 Chemical Composition
6.4 Tensile Properties
6.5 Hardenability
6.6 Hardness
6.7 Grain Size
6.8 Charpy V-Notch Impact Toughness
6.9 Resistance to Sulfide Stress Cracking (SSC)
6.10 Resistance to Hydrogen-Induced Cracking (HIC)
6.11 Resistance to Stress-Oriented Hydrogen Induced Cracking (SOHIC) and Soft Zone Cracking (SZC)
7 Marking
8 Documentation
Appendix A (Informative) Determination of CO₂ Partial Pressure
Appendix B (Informative) Material Selection Workflow for Tubing and Casing in Sour Service Environments
Appendix C (Normative) Laboratory Testing for Resistance to HIC/SWC
Appendix D (Normative) Laboratory Testing for Resistance to SOHIC/SZC
Bibliography
Petroleum and natural gas industries - OCTG used for special environment .Part 1: Recommended practice on selection of casing and tubing ofcarbon and low alloy steels for use in sour service
1 Scope
This document specifies the corrosion scenario assessment, selection principles, quality control requirements, and inspection methods for carbon and low alloy steel pipes (casing, tubing, and pup joints), coupling stock, coupling materials, and accessory materials for use in H₂S-containing oil and gas field environments.
This document is applicable to the selection of carbon and low alloy steel pipes (casing, tubing, and pup joints), coupling stock, coupling materials, and accessory materials for use in H₂S-containing oil and gas field environments.
2 Normative References
The following documents contain provisions which, through reference in this text, constitute indispensable provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 4157-2017 Laboratory testing of metals for resistance to sulfide stress cracking and stress corrosion cracking in H2S environments
GB/T 8650 Evaluation methods for resistance of linepipe and pressure vessel steels to hydrogen-induced cracking
GB/T 9253 Petroleum and natural gas industries — Gauging and inspection of casing, tubing and line pipe threads
GB/T 19001 Quality management systems — Requirements
GB/T 19830 Petroleum and natural gas industries — Steel pipes for use as casing or tubing for wells
GB/T 20972.1 Petroleum and natural gas industries — Materials for use in H2S-containing environments in oil and gas production — Part 1: General principles for selection of cracking-resistant materials
GB/T 20972.2-2008 Petroleum and natural gas industries — Materials for use in H2S-containing environments in oil and gas production — Part 2: Cracking-resistant carbon and low alloy steels, and the use of cast irons
GB/T 21267 Petroleum and natural gas industries — Procedures for testing casing and tubing connections
SY/T 5539-2013 Evaluation methods for product quality of oil country tubular goods
3 Terms, Definitions, and Abbreviated Terms
3.1 Terms and Definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
heat
Metal produced during a single cycle of melting in a furnace charge.
[Source: GB/T 19830-2023, 3.1.16]
3.1.2
inspection lot
Limited quantity of product awaiting inspection, produced under conditions that are presumed uniform.
[Source: GB/T 19830-2023, 3.1.20]
3.1.3
general corrosion
A form of corrosion distributed over the entire metal surface, causing mass loss, reduction in cross-sectional dimensions, and eventually complete failure.
3.1.4
pitting corrosion
Corrosion that results in pits on the metal surface, occurring at individual points or small areas, while most of the surface remains uncorroded or only slightly corroded in the corrosive medium.
3.1.5
crevice corrosion
Localized corrosion occurring within or adjacent to narrow gaps or clearances formed between a metal surface and another surface (metallic or non-metallic).
[Source: GB/T 10123-2022, 4.16]
3.1.6
mass loss corrosion (MLC)
A form of corrosion resulting in metal mass loss caused by electrochemical mechanisms.
Note: Includes general corrosion, pitting corrosion, and crevice corrosion.
3.1.7
manufacturer
The firm, company, or group responsible for the product, warranting its conformance to this document.
3.1.8
sulfide stress cracking (SSC)
Cracking of metal involving corrosion and tensile stress (residual and/or applied) in the presence of water and H2S.
Note: SSC is a form of hydrogen stress cracking (HSC) associated with metal embrittlement caused by atomic hydrogen originating from acid corrosion on the metal surface. The presence of sulfides promotes hydrogen absorption. Atomic hydrogen can diffuse into the metal, reducing its toughness and increasing cracking susceptibility. High-strength metals and harder weld zones are particularly susceptible to SSC.
[Source: GB/T 20972.1-2007, 3.23]
3.1.9
hydrogen-induced cracking (HIC)
Planar cracking that occurs in carbon and low alloy steels when atomic hydrogen diffuses into the steel and combines to form hydrogen molecules (H2) at traps.
Note: Cracking results from pressure build-up at hydrogen aggregation sites. HIC does not require an applied external stress. Aggregation sites capable of causing HIC are often found in areas of high impurity levels in the steel, resulting from impurity segregation and planar inclusions with high density and/or abnormal microstructural features (e.g., banding) formed by alloying elements.
[Source: GB/T 20972.1-2007, 3.12]
3.1.10
stepwise cracking (SWC)
Cracking that connects adjacent hydrogen-induced cracks on different planes in the steel.
Note: This term describes the appearance of the cracks. The stepwise cracking connecting HIC depends on local straining between cracks and the embrittlement of the steel surrounding the cracks caused by dissolved hydrogen.
[Source: GB/T 20972.1-2007, 3.20]
