Rapid permafrost thaw under buried oil pipeline and effective solution using a novel mitigative technique based on field and laboratory results

• Published in: Cold regions science and technology 2024-03, Vol.219, p.104119, Article 104119
• Main Authors: Cao, Yapeng, Ma, Wei, Li, Guoyu, Gao, Kai, Li, Changqing, Chen, Dun, Shang, Yunhu, Wei, Xiaobin, Chen, Zhixiang, Wu, Gang, Chen, Pengchao, Bai, Luyao, Tang, Liyun, Jia, Hailiang, Yue, Jianwei
• Format: Article
• Language: English
• Subjects: Air ventilation pipe; China–Russia crude oil pipeline; Permafrost; Thaw bulb; Thaw settlement
• ISSN: 0165-232X; 1872-7441
• DOI: 10.1016/j.coldregions.2023.104119

The China–Russia crude oil pipeline (CRCOP) has been in operation for over 10 years. In order to obtain the necessary data for pipeline research and provide real-time warning for pipeline operation, an in-situ composite monitoring system of pipeline–permafrost interaction along the CRCOP was established. Monitoring results has shown that a thaw bulb develops around the CRCOP, urging consolidation in strongly thawed segments. The key to maintaining the stability of warm-oil pipelines buried in permafrost is to mitigate permafrost thaw and keep the differential settlement of the pipeline in its allowable strain range. To maintain the stability of CRCOP, a novel technique is proposed to mitigate thaw settlement of underlying permafrost, preventing pipeline failure and oil spills and in turn environmental disaster. Its cooling performance is evaluated based on indoor model testing platform using in-situ monitoring data including oil temperature, ground temperature and air temperature. The initiation and development of a thaw bulb was observed around the CRCOP, urging consolidation in strongly thawed segments. Additionally, an indoor model test is conducted to verify the cooling effect of a U-shaped air ventilation duct (U-AVD). The results show that the U-AVD is conducive to mitigating permafrost thaw and removing the thaw bulb around the buried pipeline in the cold season. The findings in this article can provide a reference for studies on the CRCOP and other pipeline engineering in permafrost regions. •In-site monitoring system reveal that the permafrost surrounding the CRCOP is thawing.•A novel U-AVD is employed and its heat transfer performance is assessed.•The thaw bulb surrounding pipelines is consistently present due to pipeline heat through the year.•U-AVD is effective at mitigating permafrost degradation using ambient cool energy.