The buried China-Russia Crude Oil Pipeline (CRCOP), with its oil temperature above 0 °C, interacts complexly with the permafrost environment, causing permafrost degradation, frost geohazards, and various environmental issues along its route. 

Prof. LI Guoyu’s team from the Northwest Institute of Eco-Environment and Resources (NIEER) of the Chinese Academy of Sciences (CAS) established an on-site comprehensive monitoring system to reveal the geomorphological reshaping and water erosion caused by thawing permafrost along the CRCOP.  

The researchers observed a gradual increase in oil temperature, causing the permafrost around the CRCOP to rapidly warm and thaw. At a distance of 2 m from the pipeline center, the permafrost table decreased at a rate of 0.68 m/a, reaching a depth of -11.4 m by 2022. 

The thawing of permafrost caused pipeline settlement and ground surface subsidence, resulting in thermal erosion, water ponding in summer and icings in winter. The area near the pipeline experienced significant surface subsidence, creating lowlands that led to water ponding in summer.  

The thermal erosion of ponding accelerated topographical changes. The subsidence rate in ponding areas was 8.18 cm/a, which was significantly higher than the rate of 4.81 cm/a in non-ponding areas. 

Additionally, they proposed a series of technologies to mitigate permafrost thawing and control pipeline settlement, including thermosyphons, air ventilation ducts, and air convection pipeline embankments, ensuring safe operation of the CRCOP. 

Finally, they discussed the impacts of climate warming, fires, and human activities on permafrost degradation, illustrating the evolution process of talik and surface characteristics under the influence of multiple factors. The study provides significant data for the safe operation and maintenance of the CRCOP. 

The study, entitled "Permafrost thawing caused by the China-Russia Crude oil pipeline based on multi-type data and its impacts on geomorphological reshaping and water erosion", was published in CATENA on Jun. 4.  

Surface subsidence and water ponding along the CRCOP (Image by NIEER) 

Contact: 

GAO Kai 

E-mail: gaokai@nieer.ac.cn