Gels for profile control in enhanced oil recovery under harsh conditions
AssigneeMobil Oil Corporation
InventorsDennis H. Hoskin, Thomas O. Mitchell, Paul Shu
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Abstract
A composition of matter where a polymer is partially hydrolyzed to form a polymer intermediate which can be gelled. Said polymer intermediate consists of 2-acrylamido-2-methylpropane-3 sulfonate, N-vinyl-N-methyl acetamide, acrylamide, and an alkali metal hydroxide. When cross-linked with a transitional metal ion said polymer intermediate forms a gel suitable for profile control use under harsh conditions. Said gel is exceptionally stable under the hot temperature and saline conditions encountered in profile control usage during a water flood or carbon dioxide oil recovery operation.
Claims15
An aqueous cross-linked gel formed by partially hydrolyzing an aqueous solution of a terpolymer comprising:
- (a)
- (i) 5 to 95% by weight of 2-acrylamido-2-methylpropane-3-sulfonate;
- (ii) 5 to 95% by weight of N-vinyl-N-methyl acetamide;
- (iii) 0 to 80% by weight of acrylamide where said terpolymer is refluxed with an alkali metal hydroxide in an amount of from about 0.5 to about 5.0% by weight for about 7 to about 16 hours at a temperature of about 100.degree. C. thereby forming a polymer intermediate which can be gelled to form a gel of a size sufficient for profile control;
- and
- (b) thereafter crosslinking said intermediate with sufficient transition metal ions, melamine/formaldehyde resin or resorcinol/formaldehyde resin, thereby causing said intermediate to form a gel of a size sufficient for profile control.
An aqueous cross-linked gel formed by partially hydrolyzing an aqueous solution of a terpolymer comprising:
- (a)
- (i) 5 to 95% by weight of 2-acrylamido-2-methylpropane-3-sulfonate;
- (ii) 5 to 95% by weight of N-vinyl-N-methyl acetamide;
- (iii) 0 to 80% by weight of acrylamide where said terpolymer is refluxed with sodium hydroxide in an amount of from about 0.5 to about 5.0% by weight for about 7 to about 16 hours at a temperature of about 100.degree. C. thereby forming a polymer intermediate which can be gelled;
- and
- (b) thereafter crosslinking said intermediate with sufficient transition metal ions, melamine/formaldehyde resin or resorcinol/formaldehyde resin, thereby causing said intermediate to form a gel of a size sufficient to plug a previously swept portion of a hydrocarbonaceous fluid containing formation.
Dependencies are inferred from the claim text.