Technical scheme design for inline detection of high-risk long-distance submarine pipeline

Abstract

The status of pipeline can be effectively evaluated by identifying the defects with inline inspection technology to further improve the integrity management of oil and gas pipelines. For example, a 60 km long submarine pipeline,comprising the onshore and offshore sections, was equipped with compensators composed of hundreds of elbows in whole line, while the submarine pipeline section was seriously deformed, and the inline inspection operation faced a high risk of jamming. In view of the above characteristics, a new mechanical pig with high passing capacity was designed for diameter measurement and pigging, of which the passing capacity was verified by pull test on the test section. Subsequently, the length, flange diameter and weight of the inline detector were improved according to the diameter measurements to enhance the passing capacity of the inline detector and the fatigue resistance of elbows. Finally, the eddy current inline detector was successfully applied to the actual projects based on the progressive pigging, with the complete and effective data of the whole pipeline collected. The results show that the inline inspection technical scheme for long-distance submarine pipelines with many bends and deformation is safe and reliable, which could provide a reference for the inline inspection of other high-risk submarine pipelines.

Keywords

• submarine pipeline
• compensator
• pipeline deformation
• inline inspection
• technical scheme
• high passing capacity