Work to Enable Gas Production, Transport, and Processing

Kobayashi and coworkers (Sloan et al., 1976 Song and Kobayashi, 1982, 1984) and workers in the CSM laboratory (Sloan et al., 1986, 1987) have measured concentrations of water in hydrate-forming fluid phases in equilibrium with hydrates (when there is no free-water phase present) for application in single phase pipelines in cold regions, such as the North Slope or subsea. The trend in deepwater pipelines appears to be toward multiphase transmission (Shoup and Shoham, 1990) and their inhibition. 

In Scotland, Danesh, Todd, and coworkers measured the inhibition of multiphase systems with methanol (Avlonitis, 1994) and mixed electrolyte solutions (Tohidi et al., 1993,1994a, 1995b,c). They also performed the most comprehensive study of systems with heavy hydrocarbons such as might be produced/transported intheNorth Sea (Avlonitis et al., 1989 Tohidi etal., 1993,1994b, 1996) including systems with structure H hydrate formers. 

Hydrate formation is a substantial problem in deepwater production and flowlines. Pipelines that transport condensed hydrocarbon phases such as gas condensate or crude oil have limited possibilities for removing hydrates once the plugs have formed. Earlier work by Scauzillo (1956), indicating that formation may be inhibited by the input of hydrocarbon liquids, cannot be confirmed by thermodynamic calculations, and Skovborg (1993) has found counter-examples. Thus, the construction of large-scale pilot flow loops have been completed by large corporations such as ExxonMobil (Reed et al., 1994), Tulsa University, and Institut Francais du Petrole. Such experiments are discussed briefly in Chapter 6. 

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