The challenges in the construction and operation of oil pipelines in the cryolithozone (permanently frozen soils)

This paper examines the challenges associated with maintaining stable oil pipeline performance in complex natural and climatic conditions. The aim is to analyze issues related to permafrost that influence the design, construction methods, and long-term operation of pipelines until they reach their limit state. The tasks: identifying the causes of pipeline deformation in areas of permafrost; reviewing protective measures that help maintain pipeline stability in cryogenic conditions; describing the physical processes behind seasonal cooling devices that keep thawed soils at stable subzero temperatures during the summer. The authors of this paper employ a systems-based engineering and geocryological approach that integrates the analysis of cryogenic soil structure, thermal regime, and filtration-migration processes during moisture phase transitions. This study reveals that the main problems in pipeline construction and operation within permafrost include permafrost degradation (thawing), frost heave, and slope processes that lead to uneven foundation settlement and create critical stresses in the pipeline wall. To ensure stable pipeline geometry, the authors recommend the following protective measures: polyurethane foam insulation to stabilize the thermal regime; seasonal cooling devices that operate during summer, movable supports made of cold-resistant steels with fluoropolymer-based bearing components to compensate for thermal displacements. Using operational data the authors can conclude that underground installation at a depth of 2.5 to 3 meters is a technically and economically sound solution for permafrost regions, ensuring safe operation for up to 30 years. At the same time, above-ground installation remains relevant in Arctic areas with highly ice-rich soils, where thaw depths can produce deformations exceeding 500 mm. This study achieves its aim by identifying key permafrost-related factors that influence pipeline design, construction methodology, and long-term operation.