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Long‐term variability of pipeline–permafrost interactions in north‐west Siberia
Author(s) -
Seligman Ben J.
Publication year - 2000
Publication title -
permafrost and periglacial processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.867
H-Index - 76
eISSN - 1099-1530
pISSN - 1045-6740
DOI - 10.1002/(sici)1099-1530(200001/03)11:1<5::aid-ppp335>3.0.co;2-c
Subject(s) - permafrost , pipeline transport , compressor station , jacking , geology , gas compressor , frost weathering , environmental science , frost (temperature) , arctic , geotechnical engineering , soil water , geomorphology , oceanography , engineering , soil science , environmental engineering , mechanical engineering , art , performance art , art history
This paper identifies a long‐term (approximately 30 year) pattern in variability of pipeline–permafrost interactions in north‐west Siberia, which has serious implications for reliability of gas pipelines operating in the region. It is shown that the presence or absence of an artificial warming influence (compressor stations or gas processing plants) is the most important factor influencing interaction variability. In the early 1970s, before the installation of multiple compressor stations, large sections of trunk gas pipeline transmitted cool gas (below 0 °C), favouring the dominance of frost action, leading to frost jacking. The commissioning of multiple compressor stations from the mid 1970s and gas processing plants at one gas field in the 1980s with inadequate gas cooling was responsible for initiation of a technogenic process known as the ‘thaw→freeze–thaw process’. It is caused by transmission of warm gas (invariably well above 0 °C) through trunk and gathering pipelines buried in permafrost. Evolution of the process is most rapid in close proximity to the warming influence (within 20 km) and in areas of continuous permafrost with high volumetric ice content. Interactions are initially dominated by thaw‐related displacement of pipelines, followed by the upward flotation of buoyant, poorly ballasted pipes in soils that have lost load‐bearing capacity. Pipelines that have floated up are exposed to extreme fluctuations in seasonal air temperatures, chilling the gas in winter and warming it in summer. This leaves a pipeline vulnerable to freeze–thaw processes, such as jacking, and build‐up of stresses in pipe steel. It is suggested that these problems could be avoided by regulating (cooling) gas temperatures from the moment a new pipeline is commissioned and not after several years of operation. Copyright © 2000 John Wiley & Sons, Ltd.