Numerical Simulation of the Minimum Insulation Thickness to Thermally Design a Subsea Pipeline Carrying an Oil and Gas Flow

Abstract

This paper considered an existing subsea pipeline transporting an oil and gas flow, and proposed to find the best thermal insulating material and the required thickness of insulation necessary to meet an output temperature of 40℃ and a pressure of 2.4MPa so as to avoid flow assurance issues. MATLAB and PIPESIM software were employed to run the simulations of the temperature and pressure profiles along the considered pipeline. Data used for the simulations were obtained from open literature. Results obtained from our simulations in MATLAB are validated using PIPESIM software, measured values and prediction model from literature. The temperature model was then used to thermally design an insulation thickness for the 50 km long pipeline using three insulating materials which are: black aerogel, polyurethane and calcium silicate. Results from the analysis showed that the black Aerogel material with a critical thickness of 10.16 cm is most effective to satisfy the criterion design. The effect of the selected insulating material was also investigated on the phase envelop. Results shows that for proper insulation thickness the flowing fluid temperature can be maintained at a temperature above which no flow assurance issues can be observed.