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Characterizing alcohol and brine sensitivities of EOR surfactant systems

Book ·
OSTI ID:141329
; ;  [1]
  1. Winfrith Technology Centre, Dorchester (United Kingdom)
Surfactant systems can increase oil recovery provided they produced near optimal phase behavior in a reservoir. To select the injectant to achieve this on mixing with reservoir fluids, requires a clear understanding of the effects of the system components on the phase behavior. New concepts are presented in this paper for quantifying the sensitivity of surfactant systems to salinity and cosurfactant concentration changes. The approach identifies the characteristic parameters as concentrations in the psudobrine phase. This enables combinations of parameters resulting in suboptimal, optimal and superoptimal phase behavior, defined in terms of microemulsion oil/water ratio, to be identified independent of secondary compositional effects such as the overall oil/water ratio. The approach has been applied to an experimental study of an anionic surfactant, alcohol cosurfactant system in which the salinity was varied over a wide range. This shows that the phase behavior of the system is much more sensitive to changes in conditions at low salinities than at higher salinities typical of sea water. The observed equivalence between salinity and cosurfactant concentration is explained using electrochemical theory, giving useful insight into the role of the cosurfactant concentration is explained using electrochemical theory, giving useful insight into the role of the cosurfactant and suggesting that the results have a general relevance to anionic surfactant/cosurfactant systems.
OSTI ID:
141329
Report Number(s):
CONF-930304--
Country of Publication:
United States
Language:
English