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Carboxylate surfactant systems exhibiting phase behavior suitable for enhanced oil recovery
Author(s) -
Shaw J. E.
Publication year - 1984
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02542250
Subject(s) - microemulsion , chemistry , pulmonary surfactant , phase (matter) , decane , volume fraction , carboxylate , fraction (chemistry) , salinity , sodium bicarbonate , surface tension , salt (chemistry) , volume (thermodynamics) , carbonate , enhanced oil recovery , chromatography , organic chemistry , chemical engineering , biochemistry , geology , thermodynamics , engineering , oceanography , physics
A large variety of aliphatic and aromatic carboxylate surfactants with alcohols as cosurfactants displayed phase behavior with n‐decane that indicated they could be useful in enhanced oil recovery. Three‐phase systems with large volume fraction middle‐phase microemulsions were observed with sodium isostearate and sodium oleate. The interfacial tension between top and bottom phases was at a minimum (∼0.001 dyne/cm) at the optimal salinity where the uptake of oil and water in the middle phase was equal. The phase behavior of carboxylates was affected by pH and added bases. In cases where a bicarbonate‐carbonate buffer was used to control pH, the optimal salinity decreased as the pH decreased. Use of ethoxylated alcohols as cosurfactants increased optimal salinities markedly and caused formation of very large volume fraction middle phases. Neutralized tall oils and tall oil fatty acids with alcohols as cosurfactants gave 3‐phase behavior with n‐decane with large volume fraction middle‐phase microemulsions.