Safety Aspects of Hydrates

There are four safety aspects associated with hydrates that should be mentioned in order of decreasing importance  

When hydrates plug pipelines they are usually removed through depressurization, sometimes depressurizing only one side of the plug. 

Chapter 8 gives the evidence that plugs dissociate first at the pipewall, thus becoming a projectile in a pipeline with substantial momentum, relative to the gas phase. Lysne (1995, p. 78) lists three such incidences in which hydrate projectiles erupted from pipelines at elbows and caused the loss of three lives and over US 7 million in capital costs. Where possible, depressurization from both sides of a plug is recommended. 

In the past, hydrates have been associated with significant movement of earth (seafloor slumps) in deepwater ocean environments. Notably, Bugge et al. (1988), Schmuck and Pauli (1993), MacDonald et al. (1994), and Pauli and Dillon (2001) have described both large and small Earth movements associated with hydrates. Concerns have been expressed (Campbell, 1991) about the effect of hydrates on foundations of platforms and pipelines, as well as offshore drilling. Hydrates as geohazards are discussed in Section 7.8. 

Hydrates have also been the source of speculation of long-range climate change and safety in the greenhouse effect (Leggett, 1990). Hydrates in climate change are discussed in Section 7.8. 

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