Salt-tolerant star macromolecules

• US 10,259,901 B2
• Filed: 01/25/2017
• Issued: 04/16/2019
• Est. Priority Date: 02/04/2013
• Status: Active Grant

• Current Assignee: Pilot Polymer Technologies Incorporated
• Original Assignee: Pilot Polymer Technologies Incorporated
• Inventors: Huang, Liang, Liao, Yuanxi, McCarthy, Patrick
• Primary Examiner(s): Sastri, Satya B
• Application Number:
  US15/415,371
• Publication Number:
  US 20170355803A1
• Time in Patent Office: 811 Days
• CPC Class Codes: C08F 220/1804 C4-(meth)acrylate, e.g. butyl (meth)acrylate, isobutyl (meth)acrylate or tert-butyl (meth)acrylate
• CPC Class Codes: C08F 2438/01 Atom Transfer Radical Polymerization [ATRP] or reverse ATRP
• CPC Class Codes: C08F 293/005 using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
• CPC Class Codes: C08F 8/12 Hydrolysis
• CPC Class Codes: C08J 2300/206 Star polymers
• CPC Class Codes: C09K 8/035 Organic additives

Abstract

The present invention relates to multi-arm salt-tolerant star macromolecules, and methods of preparing and using the same. In one aspect of the invention, a salt-tolerant star macromolecule is capable of providing salt-tolerance to an aqueous composition.

Claims

1. A salt-tolerant star macromolecule, comprising:

i) a core;

ii) a plurality of hydrophilic polymeric arms; and

iii) at least one-salt-tolerant-enhancing copolymeric arm, comprising;

a) a hydrophilic polymeric segment proximal to the core; and

b) a salt-tolerant-enhancing polymeric segment distal to the core;

wherein;

1) the salt-tolerant star macromolecule, when dissolved in water at a concentration of at least 0.3 wt. % forms a homogeneous gel; and

2) the formed homogeneous gel has a dynamic viscosity at 80°

C. that is at least 50% relative to viscosity of the gel at 25°

C., according to the Temperature Stability Test.

2. The salt-tolerant star macromolecule of claim 1, wherein the salt-tolerant star macromolecule has a dynamic viscosity in a NaCl-containing aqueous solution that is greater than the dynamic viscosity at 0.0 wt. % NaCl aqueous solution, according to the Salt Tolerance Test.

3. The salt-tolerant star macromolecule of claim 1, wherein the salt-tolerant star macromolecule has an increase in dynamic viscosity with an increase in NaCl concentration, according to the Salt Tolerance Test.

4. The salt-tolerant star macromolecule of claim 1, wherein the dynamic viscosity of the salt-tolerant star macromolecule in a 0.2 wt % NaCl aqueous solution is at least 40% of the dynamic viscosity at 0.0 wt. % NaCl aqueous solution, according to the Salt Tolerance Test.

5. The salt-tolerant star macromolecule of claim 1, wherein the salt-tolerant-enhancing polymeric segment comprises:

i) repeat units of monomeric residues of one or more polymerized salt-tolerant-enhancing monomers; and

ii) optionally, repeat units of monomeric residues of one or more polymerized hydrophobic or hydrophilic monomers.

6. The salt-tolerant star macromolecule of claim 1, wherein the salt-tolerant star macromolecule is represented by Formula Z:

7. The salt-tolerant star macromolecule of claim 1, wherein the salt-tolerant star macromolecule has a molecular weight (Mn) in the range of from 5,000 g/mol to 10,000,000 g/mol.

8. The salt-tolerant star macromolecule of claim 1, wherein the arms of the salt-tolerant star macromolecule independently have a molecular weight (Mn) in the range of from 1,000 g/mol to 250,000 g/mol.

9. The salt-tolerant star macromolecule of claim 1, wherein the dynamic viscosity of the salt-tolerant star macromolecule at 60°

C. is at least 60% relative to viscosity of the gel at 25°

C., according to the Temperature Stability Test.

10. A salt-tolerant thickening agent, comprising the salt-tolerant star macromolecule of claim 1.

11. A method of making an aqueous composition salt-tolerant, comprising:

adding at least 0.3 wt. % of the salt-tolerant star macromolecule of claim 1 to the aqueous composition; and

wherein the salt-tolerant star macromolecule when dissolved in water at a concentration of at least 0.3 wt. % forms a homogeneous gel and has a dynamic viscosity of at least 10,000 cP in a 0.4 wt. % NaCl aqueous solution, according to the Salt Tolerance Test.

12. The salt-tolerant star macromolecule of claim 1, wherein the salt-tolerant star macromolecule, when dissolved in water a concentration of 0.4% wt. %, forms a homogenous gel;

and has a dynamic viscosity of at least 20,000 cP at a pH between 5.5-11.

13. The salt-tolerant star macromolecule of claim 5, wherein the monomeric residues of one or more polymerized salt-tolerant-enhancing monomers present within the salt-tolerant-enhancing polymeric segment comprise methyl acrylate or methyl methacrylate.

14. The salt-tolerant star macromolecule of claim 13, wherein the monomeric residues of one or more polymerized hydrophobic monomers present within the salt-tolerant-enhancing polymeric segment comprise styrene.

15. A composition, comprising the salt-tolerant star macromolecule of claim 1.

16. The composition of claim 15, wherein the composition is an aqueous composition.

17. The composition of claim 16, wherein the composition is a fracturing fluid composition.