Drilling fluid with improved fluid loss and viscosifying properties

Patent metadata

Field	Value
Publication number	US-10858566-B2
Application number	US-202016848338-A
Country	US
Kind code	B2
Filing date	Apr 14, 2020
Priority date	Apr 14, 2020
Publication date	Dec 8, 2020
Grant date	Dec 8, 2020

Abstract

The invention relates to a water-soluble branched sulfonated amphoteric polymer, for a water-based drilling fluid, wherein the polymer is obtained by precipitation polymerization, in a mixture of polar solvents, of at least one N,N′-dialkylacrylamide monomer and one sulfonic acid-containing monomer, in the presence of tetraallylammonium halide as branching agent.
The invention also relates to a water-based drilling fluid for subterranean boreholes, including:
an aqueous fluid, said aqueous fluid being selected from sea water, brine, or salt-containing aqueous solution, between 0.1 and 5.0 weight percent of the water-soluble branched sulfonated amphoteric polymer described above.

First claim

The invention claimed is:

1. A water-soluble branched sulfonated amphoteric polymer, for a water-based drilling fluid, wherein the polymer is obtained by precipitation polymerization, in a mixture of polar solvents, of at least one N,N′-dialkylacrylamide monomer and one sulfonic acid-containing monomer, in the presence of tetraallylammonium halide as branching agent, wherein said water-soluble branched sulfonated amphoteric polymer has a Huggins coefficient that is stable after 7 days at 300° F., as determined by a variation in the Huggins coefficient of less than 10%.

2. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the tetraallylammonium halide is tetraallylammonium chloride.

3. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the water-soluble branched sulfonated polymer comprises between 0.1 and 5.0 weight percent of tetraallylammonium halide based on the total weight of its monomers.

4. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the water-soluble branched sulfonated polymer comprises between 0.1 and 5.0 weight percent of tetraallylammonium chloride based on the total weight of its monomers.

5. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the sulfonic acid-containing monomer is selected from the group consisting of 2-acrylamido-2-methyl propane-sulfonic acid, 2-methacrylamido-2-methylpropane-sulfonic acid, sulfonated styrene, and allyl ether sulfonic acids and their corresponding salts.

6. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the water-soluble branched sulfonated amphoteric polymer contains between 50 and 99.9 mole percent of sulfonic acid-containing monomer based on the total number of moles of its monomers.

7. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the sulfonic acid-containing monomer is sodium 2-acrylamido-2-methylpropane-sulfonate.

8. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the N,N′-dialkylacrylamide is selected from N,N′-dialkylacrylamide having C 1 to C 14 alkyl groups.

9. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the N,N′-dialkylacrylamide is N,N′-dimethylacrylamide or acryloyl morpholine.

10. The water-soluble branched sulfonated amphoteric polymer of claim 1 , wherein the mixture of polar solvents is a mixture of 2-methyl-2-propanol/water having a weight ratio between 90/10 and 99/1.

11. A water-based drilling fluid for subterranean boreholes, comprising:
an aqueous fluid selected from sea water, brine, or salt-containing aqueous solution,
between 0.1 and 5.0 weight percent of the water-soluble branched sulfonated amphoteric polymer of claim 1 .

12. The water-based drilling fluid of claim 11 , wherein the water-soluble branched sulfonated amphoteric polymer contains between 50 and 99.9 mole percent of sodium 2-acrylamido-2-methylpropane-sulfonate, between 0.1 and 50 mole percent of N,N-dimethylacrylamide and between 0.1 and 5 weight percent of tetraallyl ammonium halide.

13. The water-based drilling fluid of claim 11 , wherein the water-soluble branched sulfonated amphoteric polymer contains between 50 and 99.9 mole percent of sodium 2-acrylamido-2-methylpropane-sulfonate, between 0.1 and 50 mole percent of acryloyl morpholine and between 0.1 and 5 weight percent of tetraallyl ammonium halide.

14. The water-based drilling fluid of claim 11 , wherein the water-soluble branched sulfonated amphoteric polymer contains between 50 and 99.9 mole percent of sodium 2-acrylamido-2-methylpropane-sulfonate, between 0.1 and 50 mole percent of N,N-dimethylacrylamide and between 0.1 and 5 weight percent of tetraallyl ammonium chloride.

15. The water-based drilling fluid of claim 11 , wherein the water-soluble branched sulfonated amphoteric polymer contains between 50 and 99.9 mole percent of sodium 2-acrylamido-2-methylpropane-sulfonate, between 0.1 and 50 mole percent of acryloyl morpholine and between 0.1 and 5 weight percent of tetraallyl ammonium chloride.

Assignees

• Spcm Sa

Inventors

• Favero Cédrick
• Giovanneti Bruno
• Ratel Olivier
• Cheucle Pierrick

Classifications

• C09K8/035

  Organic additives · CPC title

• C08F220/585

  and containing other heteroatoms, e.g. 2-acrylamido-2-methylpropane sulfonic acid [AMPS] · CPC title

• C09K8/12 Primary

  containing synthetic organic macromolecular compounds or their precursors · CPC title