Unit 1 1
Passage 1 Pipeline Basics 1
Passage 2 The Alaska Pipeline 12
Unit 2 14
Passage 1 Types of Natural Gas Pipelines 14
Passage 2 The GIS Introduction 23
Unit 3 28
Passage 1 In-line Inspections （Smart Pig） 28
Passage 2 Inspection of the Corrosion State of Underground Pipelines 41
Unit 4 45
Passage 1 Pipeline Repairs 45
Passage 2 How to Recognize a Natural Gas Leak 56
Unit 5 60
Passage 1 Reasons of Pipeline Corrosion 60
Passage 2 Pipe Coatings 69
Unit 6 72
Passage 1 Valves 72
Passage 2 Gas Hydrate Primer 86
Unit 7 93
Passage 1 Pipeline Construction （Ⅰ） 93
Passage 2 The Pipe Jacking （Ⅰ） 109
Unit 8 112
Passage 1 Pipeline Construction （Ⅱ） 112
Passage 2 The Pipe Jacking （Ⅱ） 129
Glossary 131