Compositions and systems for combatting lost circulation and methods of using the same

Patent metadata

Field	Value
Publication number	US-9890319-B2
Application number	US-62132909-A
Country	US
Kind code	B2
Filing date	Nov 18, 2009
Priority date	Nov 18, 2009
Publication date	Feb 13, 2018
Grant date	Feb 13, 2018

Abstract

A method of servicing a wellbore in a subterranean formation comprising preparing a composition comprising a base fluid, a thixotropic viscosifier, a gellable composition and a bridging material, applying a shear force to the composition such that the composition viscosity decreases, introducing the composition into a lost circulation zone in the subterranean formation, wherein the lost circulation zone comprises cavities greater than about 200 microns in diameter, decreasing the shear force applied to the composition, and allowing the composition to set in the lost circulation zone. A method of servicing a wellbore in a subterranean formation comprising placing a first stream comprising a dilute solution of a metal acrylate into a lost circulation zone in the subterranean formation, placing a second stream comprising an activator into the lost circulation zone, and forming a lost circulation material upon contacting of the metal acrylate and the activator, wherein the lost circulation material forms in from about 0 to about 60 minutes.

First claim

What is claimed is:

1. A method of servicing a wellbore in a subterranean formation comprising:
circulating a drilling fluid in the wellbore;
losing a portion of the drilling fluid to a lost circulation zone in the subterranean formation, wherein the lost circulation zone comprises cavities and the cavities comprise slots having widths ranging from 500 to 5000 microns;
preparing a composition comprising a base fluid, a thixotropic viscosifier, a gellable composition and a bridging material;
applying a shear force to the composition such that the composition viscosity decreases;
introducing the composition into the lost circulation zone wherein the composition has a pump time of from about 30 min to about 48 hrs;
decreasing the shear force applied to the composition; and
allowing the composition to set in the lost circulation zone,
wherein the thixotropic viscosifier comprises an associative polymer thickener selected from the group consisting of a cellulose-based polymer, an amorphous pyrogenic silica, an alkali swellable latex, a polysaccharide, and combinations thereof,
wherein the gellable composition gels by thermal activation and
wherein the composition in the absence of the bridging material has a viscosity of from about 5 centipoise to about 5000 centipoise.

2. The method of claim 1 , wherein the composition is introduced to the lost circulation zone as a single pill.

3. The method of claim 1 , wherein the thixotropic viscosifier has a density of from about 0.5 g/cc to about 4.0 g/cc.

4. The method of claim 1 , wherein the thixotropic viscosifier has a viscosity of from about 100 cp to about 2,000,000 cp.

5. The method of claim 1 , wherein the thixotropic viscosifier has a yield stress of from about 40 Pascals to about 40,000 Pascals.

6. The method of claim 1 , wherein the thixotropic viscosifier has a shear stress history response of from about 1000 to about 10 million.

7. The method of claim 1 , wherein the gellable composition comprises polyacrylamide, acrylate and polyethylene imine.

8. The method of claim 1 , wherein the bridging material comprises resilient graphite.

9. The method of claim 1 , further comprising
removing the set composition by contacting the set composition with an acid.

10. The method of claim 1 , wherein the thixotropic viscosifier is present within the composition in an amount of from about 0.1% to about 20% by weight of the base fluid.

11. The method of claim 1 , wherein the gellable composition is present within the composition in an amount of from about 0.2% to about 30% by weight of the composition.

12. The method of claim 1 , wherein the composition forms a ringing gel.

13. The method of claim 1 , wherein the gellable composition comprises a copolymer of acrylamide and t-butyl acrylate and a cross-linking agent comprising polyethylene imine.

14. The method of claim 13 , wherein the cross-linking agent is encapsulated.

15. The method of claim 1 , wherein the composition has a gel time of from about 1 hour to about 96 hours.

16. The method of claim 1 , wherein the associative polymer thickener is the cellulose-based polymer, and the cellulose-based polymer is a pseudoplastic.

17. The method of claim 1 , wherein the associative polymer thickener comprises a cellulose-based polymer, and the cellulose-based polymer is selected from the group consisting of cellulose ethers, methylcellulose, hypromellose, ethylhydroxycellulose, methylhydroxyethylcellulose, and hydroxypropylcellulose.

18. The method of claim 1 , wherein the associative polymer thickener comprises a polysaccharide, and the polysaccharide is selected from the group consisting of xanthan, diutan, gellan, gum tragacanth, and pestan.

19. The method of claim 1 , wherein the associative polymer thickener comprises an amorphous pyrogenic silica, and the amorphous pyrogenic silica has a diameter of less than about 100 nm.

20. The method of claim 1 , wherein introducing the composition into the lost circulation zone comprises introducing components in a single flowpath separated by a spacer,
wherein the components are at least two of the base fluid, the thixotropic viscosifier, the gellable composition, and the bridging material.

21. The method of claim 1 , wherein the base fluid comprises less than about 50% of a nonaqueous component.

22. The method of claim 1 , wherein the base fluid comprises an inorganic monovalent salt, a multivalent salt, or both.

23. The method of claim 22 , wherein the inorganic monovalent salt, the multivalent salt or both are present in the base fluid in an amount of from greater than about 0% by weight to a saturated salt solution.

Assignees

• Ezell Ryan G
• Reddy B Raghava
• Halliburton Energy Services Inc

Inventors

• Ezell Ryan G
• Reddy B Raghava

Classifications

• C09K8/512

  containing cross-linking agents · CPC title

• C09K8/508

  macromolecular compounds {(C09K8/512 takes precedence)} · CPC title

• C09K8/5045 Primary

  containing inorganic compounds · CPC title