Cement isolation fluids for wellbores, methods of making, and methods of use

Patent metadata

Field	Value
Publication number	US-9650559-B2
Application number	US-201514643138-A
Country	US
Kind code	B2
Filing date	Mar 10, 2015
Priority date	Mar 10, 2015
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A cement isolation fluid for use in a wellbore during a cementing operation includes an aqueous carrier fluid and a preformed synthetic polymer swellable in the carrier fluid, in an amount effective to isolate a cement slurry from another drilling fluid present in the wellbore. A method of cementing a wellbore comprising a drilling fluid includes injecting the cement isolation fluid into the wellbore; injecting a cement slurry into the wellbore; and hardening the cement in the slurry to cement the wellbore.

First claim

The invention claimed is:

1. A cement isolation fluid for use in a wellbore comprising:
an aqueous carrier fluid; and
a preformed synthetic polymer swellable in the carrier fluid in an amount effective to isolate a cement slurry from another drilling fluid present in the wellbore during a cementing operation,
the preformed synthetic polymer comprising a copolymer of (meth)acrylamide with one or more of the following, maleic anhydride, vinyl acetate, ethylene oxide, ethylene glycol, or acrylonitrile;
poly(acrylamide) having crosslinks derived from polyethylene glycol diacrylate;
poly(acrylic acid) having crosslinks derived from a vinyl ester oligomer;
a poly(acrylic acid) partial sodium salt-graft-poly(ethylene glycol); or
a copolymer of acrylic acid and a salt thereof having crosslinks derived from polyethylene glycol diacrylate; and
the preformed synthetic polymer being present in the cement isolation fluid in a concentration of about 1 pound to about 150 pounds per thousand gallons of aqueous cement isolation carrier fluid.

2. The cement isolation fluid of claim 1 , wherein the carrier fluid comprises fresh water, salt water, aqueous acid, aqueous base, or a combination comprising at least one of the foregoing.

3. The cement isolation fluid of claim 1 , wherein the preformed synthetic polymer is stable up to about 350° F.

4. The cement isolation fluid of claim 1 , wherein the preformed synthetic polymer comprises
a poly(acrylic acid) partial sodium salt-graft-poly(ethylene glycol).

5. The cement isolation fluid of claim 1 , wherein the preformed synthetic polymer is present in the form of particles, comprising the polymer.

6. The cement isolation fluid of claim 1 , wherein the particles are swelled and at least about 50% of the polymer particles have an average largest diameter of about 500 to about 12,000 micrometers.

7. The cement isolation fluid of claim 1 , wherein the preformed synthetic polymer is present in the cement isolation fluid in a concentration of about 10 pounds to about 100 pounds per thousand gallons of aqueous cement isolation carrier fluid.

8. The cement isolation fluid of claim 1 , further comprising guar, carrageenan, or a combination comprising at least one of the foregoing.

9. The cement isolation fluid of claim 1 , wherein the preformed synthetic polymer is present in the form of a hydrated pack of swelled polymer particles.

10. A method of cementing a wellbore comprising a drilling fluid, the method comprising
injecting the cement isolation fluid into the wellbore;
injecting a cement slurry into the wellbore; and
hardening the cement in the slurry to cement the wellbore,
the cement isolation fluid for use in a wellbore comprising:
an aqueous carrier fluid; and
a preformed synthetic polymer swellable in the carrier fluid in an amount effective to isolate a cement slurry from another drilling fluid present in the wellbore during a cementing operation,
the preformed synthetic polymer comprising a homopolymer of (meth)acrylamide or a copolymer of (meth)acrylamide with one or more of the following: maleic anhydride, vinyl acetate, ethylene oxide, ethylene glycol, or acrylonitrile;
poly(acrylamide) having crosslinks derived from polyethylene glycol diacrylate;
poly(acrylic acid) having crosslinks derived from a vinyl ester oligomer,
a poly(acrylic acid) partial sodium salt-graft-poly(ethylene glycol); or
a copolymer of acrylic acid and a salt thereof having crosslinks derived from polyethylene glycol diacrylate; and
the preformed synthetic polymer being present in the cement isolation fluid in a concentration of about 1 pound to about 150 pounds per thousand gallons of aqueous cement isolation carrier fluid.

11. The method of claim 10 , wherein injecting the cement slurry is subsequent to injecting the isolation fluid.

12. The method of claim 11 , further comprising injecting a second cement isolation fluid after injecting the cement slurry.

13. The method of claim 10 , further comprising injecting a cement spacer fluid to displace the drilling fluid; subsequently injecting the cement isolation fluid; and subsequently injecting the cement slurry.

14. The method of claim 10 , wherein the cement isolation fluid prevents density swapping between the cement slurry and a drilling fluid, or between the cement slurry and a wellbore fluid.

15. The method of claim 10 , wherein the wellbore is a vertical wellbore.

16. The method of claim 10 , wherein the synthetic polymer comprises poly(acrylamide) having crosslinks derived from polyethylene glycol diacrylate.

17. The method of claim 10 , wherein the synthetic polymer comprises poly(acrylic acid) having crosslinks derived from a vinyl ester oligomer.

18. The method of claim 10 , wherein the synthetic polymer comprises a poly(acrylic acid) partial sodium salt-graft-poly(ethylene glycol).

19. The method of claim 10 , wherein the synthetic polymer comprises a copolymer of acrylic acid and a salt thereof having crosslinks derived from polyethylene glycol diacrylate.

20. The method of claim 10 , wherein the preformed synthetic polymer is present in the cement isolation fluid in a concentration of about 10 pounds to about 100 pounds per thousand gallons of aqueous cement isolation carrier fluid.

21. The method of claim 10 , wherein the preformed synthetic polymer is present in the cement isolation fluid in a concentration of about 30 pounds to about 60 pounds per thousand gallons of aqueous cement isolation carrier fluid.

22. The method of claim 10 , wherein injecting the isolation fluid is after injecting the cement slurry.

Assignees

• Nelson Scott Gregory
• Baker Hughes Inc

Inventors

• Nelson Scott Gregory

Classifications

• C09K8/40 Primary

  Spacer compositions, e.g. compositions used to separate well-drilling from cementing masses · CPC title

• E21B33/13

  Methods or devices for cementing, for plugging holes, crevices or the like · CPC title

• E21B21/00

  Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor (freeing objects stuck in boreholes by flushing E21B31/03) · CPC title

• C09K8/426

  for plugging · CPC title

• C09K8/424

  using "spacer" compositions · CPC title