Phase equilibria in the presence of saline water systems and its application to the hydrate inhibition effect of produced water

A major concern in North Sea wells is that the above subsea pipelines and process facilities are prone to hydrate formation. For efficient pipeline design and operation, phase equilibria as well as the boundary of hydrate formation, with and without salts and other chemical inhibitors, must be precisely known. Produced water, due to the presence of salts, has a hydrate inhibiting effect and hence reduces the requirement in the consumption of expensive inhibitors. The paper presents a prediction model for reservoir fluids in the presence of salts and/or chemical inhibitors. The model is capable of predicting vapor pressure and freezing point of saline systems and single and mixed electrolyte solutions.