Alkaline surfactant polymer flooding composition and process
AssigneeOil Chem Technologies
InventorsOliver YeSung Hsu, Nelson SungNan Hsu
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Abstract
An improved concentrated surfactant formulation and process for the recovery of residual oil from subterranean petroleum reservoirs, and more particularly an improved alkali surfactant flooding process which results in ultra-low interfacial tensions between the injected material and the residual oil, wherein the concentrated surfactant formulation is supplied at a concentration above, at, or, below its CMC, also providing in situ formation of surface active material formed from the reaction of naturally occurring organic acidic components with the injected alkali material which serves to increase the efficiency of oil recovery.
Claims26
A composition for enhanced oil recovery comprising a primary concentrated aqueous surfactant formulation which is added to an alkali and is diluted with brine, forming a diluted primary injection solution resulting in a primary surfactant concentration, at, or below its critical micellar concentration which is introduced into a subterranean oil reservoir, wherein said reservoir oil contains naturally occurring acidic organic components, and further wherein said diluted primary injected solution provides ultra-low interfacial tension between the residual oil and the primary injection solution allowing the alkali to permeate the microscopic of the reservoir and contact and react with said naturally occurring acidic organic component(s) forming a secondary in situ formed secondary surfactant system comprising salts with surfactant properties which combines with the diluted primary injection solution, thereby enabling the trapped residual oil to be emulsified, mobilized and brought to the surface, the primary concentrated aqueous surfactant formulation, comprising:
- a) from about 40 to about 60% by weight alkylaromatic sulfonic acid, wherein the alkyl group being linear or branched groups with carbon atoms numbering from about 4 to about 24, and wherein the aromatic group comprises benzene, naphthalene, toluene or xylene and further said alkylaromatic sulfonic acid having an average molecular weight of about 230 to about 600,
- b) from about 5 to about 30% by weight of a lower alkyl alcohol having from about 2 to about 8 carbon atoms,
- c) from about 0 to about 10% by weight nonionic surfactant, or sulfonated and carboxylated nonionic surfactants,
- d) from about 0 to about 10% by weight narrow-cut aromatic solvent,
- e) from about 0 to about 10% by weight alkylene glycol,
- f) from about 3 to about 10% strong base by weight, and
- g) water to balance.
In the process for enhanced oil recovery wherein a primary concentrated aqueous surfactant formulation is diluted with brine, and alkali, and optionally polymer, forming a diluted primary injection solution resulting in a primary surfactant concentration, at, or below its critical micellar concentration which is introduced into a subterranean oil reservoir, wherein said reservoir oil residual oil contains naturally occurring acidic organic component(s), and further wherein said diluted primary injected solution provides ultra-low interfacial tension between the residual oil and the diluted primary injection injected solution enabling the alkali to permeate the pores of the reservoir, contact and react with said naturally occurring acidic organic component(s) forming an in situ secondary surfactant system comprising salts with surfactant properties which combines with the diluted primary injection solution, thereby enabling the trapped residual oil to be emulsified, mobilized and brought to the surface, the process utilizing a primary concentrated aqueous surfactant formulation, comprising;
- a) from about 40 to about 60% by weight alkylaromatic sulfonic acid, wherein the alkyl group being linear or branched groups with carbon atom numbering from about 4 to about 24, and wherein the aromatic group comprises benzene, napthelene, toluene or xylene and further said alkylaromatic sulfonic acid having an average molecule weight of about 230 to about 600,
- b) from about 5 to about 30% by weight of a lower alkyl alcohol having from about 2 to about 8 carbon atoms,
- c) from about 0 to about 10% by weight nonionic surfactant, or sulfonated and carboxylated nonionic surfactants,
- d) from about 0 to about 10 percent by weight narrow-cut aromatic solvent,
- e) from about 0 to about 7% by weight alkylene glycol,
- f) from about 3 to about 10% by weight strong base, and
- g) water to balance.
Dependencies are inferred from the claim text.