Critical Gas Saturation: Modeling and Sensitivity Studies
1993; Linguagem: Inglês
10.2118/26662-ms
Autores Tópico(s)Phase Equilibria and Thermodynamics
ResumoABSTRACT The critical gas saturation (Sgc) is an important parameter in solution gas-drive processes. Despite considerable amount of research, however, both the concept and its values in various porous media remain unclear and a cause of confusion in the literature. Based on various definitions, values as low as 1% and as high as 27% have been reported. In this paper we present an investigation on the fundamental aspects of bubble growth and the formation of critical gas saturation in porous media. A theoretical model is developed, based on which a pore network simulator is constructed. We discuss patterns and rates of growth for single and multiple gas clusters, using statistical models, such as percolation and DLA. It is shown that in porous media, gas evolution (patterns and rates) are much different than in the bulk. The critical gas saturation is studied in terms of the system parameters, notably the nucleation fraction and the pressure decline rate. Sgc is found to be increasing with the nucleation fraction and the pressure decline rate at relatively high rates, but to be independent of the latter at sufficiently small rates. A condition for this is developed. The scaling up with system size is also discussed.
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