Composition that can form a gel comprising a copolymer, and useful copolymers

• US 7,884,056 B2
• Filed: 12/20/2005
• Issued: 02/08/2011
• Est. Priority Date: 12/21/2004
• Status: Expired due to Fees

• Current Assignee: Rhodia Chimie (Solvac SA)
• Original Assignee: Rhodia Chimie (Solvac SA)
• Inventors: Karagianni, Katerina, Pitois, Claire, Bendejacq, Denis
• Primary Examiner(s): Kugel; Timothy J.
• Application Number:
  US11/793,490
• Publication Number:
  US 20100120637A1
• Time in Patent Office: 1,876 Days
• Field of Search: 507/219, 507/221, 507/222, 507/224, 507/225, 507/230, 525/261, 525/299, 525/301, 525/302, 525/303, 525/309, 528/271, 528/363, 528/364, 528/369, 528/370, 528/374, 528/376, 528/422
• US Class Current: 507/219
• CPC Class Codes: C08F 2438/03 Use of a di- or tri-thiocarbonylthio compound, e.g. di- or tri-thioester, di- or tri-thiocarbamate, or a xanthate as chain transfer agent, e.g . Reversible Addition Fragmentation chain Transfer [RAFT] or Macromolecular Design via Interchange of Xanthates [MADIX]
• CPC Class Codes: C08F 293/005 using free radical "living" or "controlled" polymerisation, e.g. using a complexing agent
• CPC Class Codes: C09K 8/68 containing organic compounds
• CPC Class Codes: C09K 8/88 macromolecular compounds

Abstract

The invention relates to a composition that can form a gel comprising a copolymer. Said composition is an aqueous composition, and the copolymer is a star copolymer. The invention also relates to useful copolymers, especially for the inventive compositions.

Claims

1. A star copolymer comprising a core and, at the periphery of the core, macromolecular branches each comprising:

an intermediate block A linked to the core or at least partly included in the core; and

a peripheral block B linked to the block A;

wherein the weight ratio between block A and block B being greater than or equal to 40/60;

the blocks A and B being such that;

block A is hydrophilic and block B is hydrophobic;

or

block A is hydrophilic and block B is hydrophilic, cationic or potentially cationic

wherein the core is a chemically-crosslinked polymeric organic core.

2. An aqueous composition comprising:

water;

a star copolymer as defined by claim 1; and

optionally, at least one surfactant.

3. The composition as defined by claim 2, wherein:

block A is hydrophilic and block B is hydrophobic; and

the composition comprises a nonionic surfactant.

4. The composition as defined by claim 2, wherein the nonionic surfactant comprises a C₁₀-C₁₈ polyethoxylated alcohol.

5. The composition as defined by claim 2, wherein:

block A is hydrophilic and block B is hydrophilic cationic or potentially cationic; and

the composition comprises an anionic surfactant.

6. The composition as defined by claim 2, wherein:

the composition comprises from 2 to 10% by weight of the total of the star copolymer and of the surfactant; and

the ratio between the surfactant and the star copolymer is between 0 and 50/50.

7. The composition as defined by claim 2, in the form of a viscoelastic gel.

8. The composition as defined by claim 2, wherein the star copolymer, the surfactant, if present, and the amounts thereof, are such that it is in the form of a viscoelastic gel.

9. The composition as defined by claim 2, comprising a fluid for oil or gas production.

10. The composition as defined by claim 2, wherein:

the composition comprises from 2 to 10% by weight of the total of the star copolymer and of the surfactant; and

the ratio between the surfactant and the star copolymer is between 10/90 and 50/50.

11. The star copolymer as defined by claim 1, wherein block A is hydrophilic and block B is hydrophobic.

12. The star copolymer as defined by claim 11, wherein block A has a molar mass between 5,000 and 20,000 g/mol, and block B has a molar mass between 2,000 and 10,000 g/mol.

13. The star copolymer as defined by claim 1, wherein:

block A is hydrophilic and block B is cationic or potentially cationic.

14. The star copolymer as defined by claim 13, wherein block A has a molar mass between 5,000 and 70,000 g/mol and block B has a molar mass between 1,000 and 20,000 g/mol.

15. A method for controlling the formation of viscoelastic gels comprising the following steps:

a) preparing an aqueous composition comprising;

water;

a star copolymer as defined by claim 1;

optionally, a surfactant; and

b) forming a gel by stirring and/or by addition of surfactant and/or heating.

16. The method as defined by claim 15, wherein:

the composition does not comprise surfactant; and

the gel is formed by addition of an effective amount of surfactant.

17. The method as defined by claim 15, wherein:

block B is hydrophobic;

the composition comprises an amount of nonionic surfactant greater than the affective amount to form a gel; and

the gel is formed by heating.

18. The method as defined by claim 15, wherein:

the method is used during oil or gas production;

the aqueous composition is a fracturing fluid; and

the optional heating is provided by the temperature of the oil or gas.

19. The star copolymer as defined by claim 1, wherein the block A comprises hydrophilic units A_philic deriving from monomers selected from among the following monomers;

neutral hydrophilic monomers A_N from which A_N units may derive;

hydroxyethylacrylates and methacrylates, acrylamide, methacrylamide;

vinyl alcohol;

anionic or potentially anionic monomers A_A, from which anionic or potentially anionic units A_A may derive;

acrylic acid, methacrylic acid, maleic acid or anhydride, and their water soluble salts;

2-sulfooxyethyl methacrylate, vinylbenzene sulfonic acid, allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, sulfoethyl acrylate or methacrylate, sulfopropyl acrylate or methacrylate and their water-soluble salts;

if block B is hydrophobic, the hydrophilic cationic or potentially cationic monomers A_C from which the A_C units may derive.

20. The star copolymer as defined by claim 1, wherein the block B is a hydrophobic block, comprising hydrophobic units B_phobic deriving from monomers selected from among the following monomers:

styrene, α

-methylstyrene, vinyltoluene;

vinyl chloride, vinylidene chloride;

methyl, ethyl, butyl, 2-ethylhexyl acrylates and methacrylates; and

vinyl or allyl acetate.

21. The star copolymer as defined by claim 1, wherein the block B is a hydrophilic cationic or potentially cationic block, comprising cationic or potentially cationic units B_C deriving from monomers selected from among the following monomers;

N,N-dimethylaminomethyl acrylamide or methacrylamide;

2-(N,N-dimethylamino)ethyl acrylamide or methacrylamide;

3-(N,N-dimethylamino)propyl acrylamide or methacrylamide;

4-(N,N-dimethylamino)butyl acrylamide or methacrylamide;

2-(dimethylamino)ethyl acrylate (ADAM);

2-(dimethylamino)ethyl methacrylate (DMAM);

3-(dimethylamino)propyl methacrylate, 2-(tert-butylamino)ethyl methacrylate;

2-(dipentylamino)ethyl methacrylate;

2-(diethylamino)ethyl methacrylate;

vinyl pyridines;

vinyl amine;

vinyl imidazolines;

trimethylammonium propylmethacrylate chloride;

trimethylammonium ethylacrylamide chloride or bromide or trimethylammonium methacrylamide chloride or bromide;

trimethylammonium butacrylamide methyl sulfate or trimethylammonium methacrylamide methyl sulfate;

trimethylammonium propylmethacrylamide methyl sulfate (MES);

(3-methacrylamidopropyl)trimethylammonium chloride (MAPTAC);

(3-acrylamidopropyl)trimethylammonium chloride (APTAC);

(methacryloyloxyethyl)trimethylammonium chloride or methyl sulfate;

(acryloyloxyethyl)trimethylammonium chloride or (acryloyloxyethyl)trimethylammonium methyl sulfate (ADAMQUAT C1 or ADAMQUAT MeS);

1-ethyl-2-vinylpyridinium bromide, chloride or methyl sulfate, 1-ethyl-4-vinylpyridinium bromide, chloride or methyl sulfate;

N,N-dimethyldiallylammonium chloride (DADMAC); and

dimethylaminopropylmethacrylamide N-(3-chloro-2-hydroxypropyl)trimethylammonium chloride (DIQUAT).

22. The star copolymer as defined by claim 1, comprising:

a block A deriving from acrylic acid and a block B deriving from butyl acrylate;

a block A deriving from acrylamide and a block B deriving from butyl acrylate;

or

a block A deriving from acrylamide and a block B deriving from acryloyloxyethyl trimethylammonium chloride or acryloyloxyethyl trimethylammonium methyl sulfate.

23. The star copolymer as defined by claim 1, wherein the core is obtained according to a method of the “

arm first”

type or “

core first”

type.

24. The star copolymer as defined by claim 1, prepared via controlled radical polymerization.