Transportation of hydrocarbons and water in long subsea flowlines from satellite fields to a platform or to shore results in new challenges to control hydrates, corrosion and scale. As the fluids cool down, water will condense and gas hydrates will form unless an inhibitor such as mono ethylene glycol (MEG) is present. The presence of MEG changes the thermodynamics of the aqueous phase and lowers the solubility of most salts. MEG also changes the pH, the gas solubility and the acidity of CO2. Controlling scale and corrosion in such systems requires good control of pH, salt solubility, gas solubility and the effect of MEG on these parameters. This work presents a model that can accurately predict pH, scale potential, gas solubility and salt solubility in systems with MEG concentrations from 0-95wt%. The model is based on a large amount of experimental data in MEG containing systems, both from the literature and from the present work. With the model it is possible to accurately predict pH and scale potential as function of pressure, temperature, composition of water and hydrocarbon phases and MEG concentration.

You can access this article if you purchase or spend a download.