A new correlation for predicting the hydrate-free zone of reservoir fluids, from black oil to lean natural gas, has been developed. The method correlates the hydrate dissociation pressure against the specific gravity and the concentration of the hydrate-forming components in the fluid, as well as the temperature of the system. The effect of nitrogen and carbon dioxide on the hydrate-free zone has also been taken into account. The correlation has been developed using hydrate phase boundaries for 31 fluids generated by a well-proven comprehensive thermodynamic model. Hydrate phase boundaries for 13 independent reservoir fluids calculated by the new correlation and the thermodynamic model have been compared, showing a maximum error of 1.0 K in the calculated potential hydrate-forming temperature.

Keywords:
stergaard, upstream oil & gas, hydrate-free zone, reservoir fluid, petroleum engineering, hydrate dissociation pressure, natural gas, nitrogen, gas condensate, flow assurance
Subjects:
Flow Assurance, Fluid Characterization, Fluid modeling, equations of state, Hydrates, Phase behavior and PVT measurements
Copyright 2000, Society of Petroleum Engineers
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