Hydrate risk management

While accurate thermodynamic predictions enable avoidance via use of thermodynamic inhibitors such as methanol or glycol, hydrates risk management is enabled by experience in the form of experiments, both in the field and in the laboratory. This is because, as indicated in Chapter 3, there is no comprehensive, predictive hydrate kinetic theory that can be accurately invoked at high hydrate... 

Sloan, E.D. (2005). A changing hydrate paradigm—from apprehension to avoidance to risk management. Fluid Phase Equilibria, 228, 67-74. 

Chapter 8 presents problems of natural gas production, transportation, and processing which are related to hydrates. Because a standard kinetic treatment method has progressed past the fledgling state in the second edition (1998), the state-of-the-art in flow assurance is turning away from thermodynamic properties which encourage hydrate avoidance, to kinetic properties which encourage a new philosophy in flow assurance—that of risk management. 

While the past methods of preventing hydrate plugs have been to use avoidance with thermodynamic inhibitors such as methanol or glycols, our new understanding of how plugs form, allows us to propose economic risk management (kinetics) to avoid hydrate formation. These concepts differ in type for oil-dominated and gas-dominated systems. 

In the future, economic risk evaluation will guide the hydrate-plugging prevention philosophy. It is important to note that phase equilibria thermodynamics provide the current paradigm of hydrate avoidance, but risk management is in the domain of time-dependent phenomena or physical hydrate kinetics. The experience base with hydrate plugs and their remediation impacts the economic need for large amounts of insulation and/or thermodynamic inhibitors. 

While accurate thermodynamic predictions (as in Chapters 4 and 5) enable avoidance via use of inhibitors such as methanol, risk management is enabled by operating experience and by kinetic predictions. Hydrate thermodynamic predictions can provide avoidance techniques, but kinetic predictions are required to provide techniques of risk management. 

This strategy was successful in extending the field life by almost 2 years. This is one key example of the risk management philosophy, enabled by operating experience on the platform. The hydrate plug prevention technique in this case study is time-dependent and should be contrasted with thermodynamic (time-independent) inhibition methods in Case Study 4 of Canyon Express and Ormen Lange. 

The management of a bleeding ulcer is dictated by the severity of the bleed. Mr B is not particularly old, he is not shocked (pulse rate less than f 00 bpm, systolic blood pressure over 100 mmHg), and active bleeding has not been reported. He had the appropriate fluid replacement (saline, a crystalloid). Blood was not needed as he did not have particular signs of hypovolaemic shock and his haemoglobin is above 10 g/dL. He had no risk factors to suggest that antibacterial prophylaxis was necessary before endoscopy. His enalapril and furosemide were temporarily stopped, and if his blood pressure, hydration state... 

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