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US 5,311,943 AGranted
Blends of propoxy and ethoxy surfactants
AssigneeShell Oil Company
InventorScott L. Wellington
Life of this patent
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Abstract
A mixture of propoxylated and ethoxylated surfactants is provided, along with a method to displace water flood residual oil from subterranean formations utilizing this mixture. The mixture is considerably less expensive than surfactants containing both propoxy and ethoxy groups, but provides the advantages of a graded lipophilic to hydrophilic structure of such surfactants.
Claims11
A method to recover oil from a subterranean formation comprising the steps of:
- a) providing a surfactant mixture comprising at least a first surfactant, the first surfactant comprising at least one ethoxy group, a hydrophilic group, a cation, a hydrophobic radical selected from the group consisting of linear or branched alkyl radicals, and alkyl or alkenyl substituted benzene radicals, and not including any propoxy groups, and a second surfactant, the second surfactant comprising at least one propoxy group, a hydrophilic groups, a cation, a hydrophobic radical selected from the group consisting of linear or branched alkyl radicals, and alkyl or alkenyl substituted benzene radicals, and not including any ethoxy groups;
- b) injecting the surfactant mixture into the subterranean formation;
- c) displacing the surfactant mixture through the subterranean formation toward an oil production well whereby the surfactant mixture displaces oil from the formation through which it is displaced;
- and
- d) recovering the displaced oil from the oil production well.
2 more elements
Dependencies are inferred from the claim text.