1. Hydrates, Flow Assurance & Phase Equilibria Group, Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, U.K.
2. Department of Petroleum Engineering, Abubakar Tafawa Balewa University, Bauchi PMB 0248, Nigeria
3. MINES ParisTech, CTP-Centre Thermodynamique des Procédés, 35, Rue Saint Honoré, Fontainebleau 77305, France