Low PH crosslinking of polymers

Patent metadata

Field	Value
Publication number	US-10407612-B2
Application number	US-201715481426-A
Country	US
Kind code	B2
Filing date	Apr 6, 2017
Priority date	Feb 22, 2013
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

The invention is directed to polymers that self-crosslink at acidic pH or can be crosslinked by phenolic agents in brine. Such polymers have lower viscosity and can be pumped deep into reservoirs, where they will cross link in situ, thus increasing their viscosity and/or form a gel and blocking thief zones. Methods of making and using such polymers are also provided.

First claim

The invention claimed is:

1. A composition for improving sweep efficiency of a CO 2 flood in a reservoir, said composition comprising i) a polymer with one or more acrylamide based monomers in the repeat unit, wherein at least one monomer has pendant hydroxyl groups, ii) a fluid, and iii) an phenolic crosslinker, wherein said polymer has a first viscosity at pH 8 and a second higher viscosity or forms a gel when aged at a pH less than 5 in said reservoir, wherein said polymer is poly(acrylamide-N-hydroxymethylacrylamide).

2. The composition of claim 1 , wherein said phenolic crosslinker is chosen from a group containing phenol, catechin, resorcinol, phenyl acetate, salicyl alcohol, aspirin, m-cresol, phloroglucinol, quercetin, gallocatechin, naringenin, eriodictyol, afzelechin and epimers thereof.

3. The composition of claim 1 , wherein said fluid comprises CO 2 .

4. A composition comprising poly(acrylamide-N-hydroxymethylacrylamide), water or brine, and a phenolic crosslinker.

5. The composition of claim 4 , wherein said phenolic crosslinker is chosen from a group comprising phenol, catechin, resorcinol, m-cresol, phenyl acetate, salcyl alcohol, aspirin, phloroglucinol, quercetin, gallocatechin, naringenin, eriodictyol, afzelechin and epimers thereof.

6. A composition comprising poly(acrylamide-N-hydroxymethylacrylamide), water or brine, and a phenolic crosslinker selected from phenol, catechin, resorcinol, m-cresol, phenyl acetate, salcyl alcohol, aspirin, phloroglucinol, quercetin, gallocatechin, naringenin, eriodictyol, afzelechin and epimers and combinations thereof, wherein said composition has a first viscosity at pH 8 and a second higher viscosity when aged at a pH less than 5.

Assignees

• Conocophillips Co
• Univ Kansas

Inventors

• Guan Huili
• Berkland Cory
• Moradi-Araghi Ahmad
• Liang Jenn-Tai
• Christian Terry M
• Needham Riley B
• Hedges James H
• Cheng Min
• Scully Faye L

Classifications

• E21B43/164

  Injecting CO2 or carbonated water (in combination with organic material C09K8/594) · CPC title

• E21B33/138

  Plastering the borehole wall; Injecting into the formation · CPC title

• C09K8/594 Primary

  Compositions used in combination with injected gas {, e.g. CO2 orcarbonated gas}(C09K8/592 takes precedence) · CPC title

• C08F2800/10

  as molar percentages · CPC title

• Y02P90/70

  Combining sequestration of CO2 and exploitation of hydrocarbons by injecting CO2 or carbonated water in oil wells · CPC title