Predictions and observations on the behaviour of a warm gas pipeline on permafrost

Abstract

This paper deals with predictions and measured observations of the behaviour of a warm gas pipeline on permafrost. In the paper, descriptions of the theoretical background for a mathematical model developed by the Canadian Arctic Gas Study Limited will be made. The model incorporates the following aspects: (a) transient heat conduction mechanism during freezing and thawing in the ground, in which the latent heat is considered as a heat source in the energy balance equation; (b) heat exchange mechanism at the ground surface with respect to meteorological data such as ambient air temperature, solar radiation, greenhouse factor, wind velocity, snow depth, and evapotranspiration; and (c) changes in geometry of the thermal domain due to thaw subsidence.Verification of the model was made using field data obtained from a hot-berm module with a gas temperature of 65 °F (18.3 °C), at the Norman Wells Test Facility of Canadian Arctic Gas Study Limited. Good correlation was found for predicted and measured values of: (a) ground temperature profiles in instrumented locations, (b) ground surface settlement, (c) pipe settlement, and (d) heat flux around the pipe.