Code for Quality Acceptance of Oil and Gas Construction Engineering—Gathering and Transmission Pipelining Projects in Highly Hydrogen Sulfide Gas Field
1 Scope
This standard specifies the classification and contents of the unit project, subsection project, subitem project and inspection lot as well as quality acceptance procedures and standards for the gathering and transmission pipelining projects in highly hydrogen sulfide gas field.
This standard is applicable to the construction quality acceptance of the constructed, extended and renovated natural gas gathering and transmission pipelining projects with the volume fraction of H2S in the natural gas greater than or equal to 5%, except the large and medium-sized passing and crossing projects.
2 Normative References
The following documents are indispensable for the application of this standard. For dated references, only the dated edition is applicable to this document. For undated references, the latest editions of the normative documents (including all the amendments) are applicable to this document.
GB/T 4842 Argon
GB/T 20972 (All the parts) Petroleum and natural gas industries—Material for use in H2S-containing environments in oil and gas production
SY/T 0599-2006 Metallic material requirements-Resistance to sulfide stress cracking and stress corrosion cracking for gas surface equipment
SY/T 4117 Technical code for welding of gathering and transmission pipeline in highly hydrogen sulfide gas field
SY/T 4119 Technical code for construction of gathering and transmission pipeline in highly hydrogen sulfide gas field
SY 4200 Code for quality acceptance of oil and gas construction engineering-General rule
SY 4204 Code for quality acceptance of oil and gas construction engineering oil-gas field gathering and transportation pipeline engineering
Examination and Administrative Rules for Welders Specializing in Boilers and Pressure Vessels and Pressure Pipes Guo Zhi Jian Guo [2002] No. 109
3 Terms and Definitions
For the purpose of this document, the terms and definitions defined in SY/T 0599-2006 and the following ones apply.
3.1
Hydrogen induced cracking (HIC)
It refers to the plane crack in the carbon steel and low alloy steel caused by the process when the hydrogen atoms diffuse into the steel & iron and combine into the hydrogen molecules (hydrogen) in the traps.
Note: crack is generated by the pressure increase at the accumulation point of hydrogen. HIC is generated without the necessary for the external stress. The accumulation point that can cause HIC is always located where the impurity content is high in the steel, because of the impurity segregation and the planar slag inclusion with higher density and (or) the area with abnormal microstructure (such as banded structure) formed by the alloy elements in the steel. Such kind of HIC has nothing to do with the welding.
[SY/T 0599—2006, definition 3.4]
3.2
Sulfide stress cracking (SSC)
It refers to a kind of metal cracking related to the corrosion and tensile stress [residual and (or) additional] at the presence of water and H2S.
Note: SSC, a kind of hydrogen nitride stress cracking (HSC), is related to the metal brittleness on the metal surface caused by the atomic hydrogen generated by the sour corrosion, which will promote the absorption of hydrogen in the presence of sulfide. Atomic hydrogen can diffuse into metal, reduce the metal tenacity and increase the crack sensitivity. It is easy for the high-strength metal materials and hard weld area to occur SSC.
[SY/T 0599—2006, definition 3.1]
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 General Provisions
5 Basic Requirements
6 Classification of Project Quality Acceptance
7 Pipeline Prefabrication
8 Pipe Ditch Excavation
9 Pipeline Assembly
10 Pipeline Welding
11 Pipeline Anticorrosive Coating Joint Repair and Defect Repair
12 Pipeline Insulation Joint Repair and Defect Repair
13 Pipeline Ditching and Backfilling
14 Pipeline Purging and Pressure Testing
15 Pipeline Drying
16 Small-sized Passing Project
17 Small-sized Crossing Project
18 Sacrificial Anode Cathodic Protection Project
19 Impressed Current Cathodic Protection Project
20 Circuit Cut-Off Valve Room
21 Mileage Stake, Turning Point Stake and Testing Stake
22 Circuit Protection Structure Project
23 Project Handover Acceptance
Appendix A (Normative) Instruments Applied in the Engineering Quality Inspection
Appendix B (Normative) Quality Acceptance Records for Inspection Lot
