A general correlation for predicting the suppression of hydrate dissociation temperature in the presence of thermodynamic inhibitors

Thermodynamic inhibitors can be used in avoiding gas hydrate problems in natural gas and oil production and transportation. A new correlation for predicting the suppression of the hydrate dissociation temperature of various petroleum fluids in the presence of different thermodynamic inhibitors (e.g., electrolytes and organic inhibitors) is presented. The correlation, which can be applied to drilling and reservoir fluids, requires inhibitor concentration, pressure of the system and, if known, the dissociation pressure of the fluid in the presence of distilled water at 273.15 K. The correlation has been developed using hydrate phase boundaries for methane and seven natural gases in the presence of various single inhibitors generated by a well-proven comprehensive thermodynamic model. It covers nine electrolyte solutions and six organic inhibitors, which may be available and/or added to the reservoir and drilling fluids. The developed correlation is generic and could be easily extended to other salts and organic inhibitors. (C) 2005 Elsevier B.V. All rights reserved.