Prediction of Condensate Natural Gas Hydrate Forming Conditions in the Submarine Pipeline

Owing to particularity of operating conditions, submarine temperature and transporting technique, condensate gas hydrate is easy to form in the submarine pipeline. Pipeline transportation of wet gas belongs to the category of oil-gas two-phase flow, so the method for calculating operating parameters and amount of water along the offshore pipeline is not the same as usual natural gas pipeline. In this paper, hydrodynamic and thermodynamic models that used to submarine pipeline with a relatively high accuracy have been optimally selected comparing with field data of JZ 20-2 and Pinghu-Shanghai offshore pipelines carrying condensate gas. In combination with statistical thermodynamic calculation approaches,the models can predict hydrate forming conditions and determine the amount of water of condensate gas.The foregoing studies are of great importance in terms of judging hydrate forming zones,preventing the hydrates from being generated and ensuring pipeline operating safely.