Fluid loss control agents and compositions for cementing oil and gas wells comprising said fluid loss control agent

Patent metadata

Field	Value
Publication number	US-9458372-B2
Application number	US-201514597136-A
Country	US
Kind code	B2
Filing date	Jan 14, 2015
Priority date	Dec 21, 2004
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

A method of cementing a well is disclosed. The method comprising pumping into the well a cement slurry comprising a solid blend including cement, water, and a fluid loss control agent, and allowing the cement slurry to set. The fluid loss control agent comprises a styrene-butadiene latex and a high molecular-weight water-soluble polymer such as a copolymer AMPS-Am. The addition of the water-soluble polymer allows drastic reduction of the quantity of latex required to achieve fluid loss control performance and even gas migration control.

First claim

The invention claimed is:

1. A method of cementing a well, comprising:
(i) preparing a fluid-loss control agent consisting of a single mixture of a styrene-butadiene latex and an unhydrolyzed water-soluble polymer having a molecular weight between 200,000 and 4,000,000;
(ii) adding the fluid loss control agent to a cement slurry comprising cement and water; and
(iii) placing the slurry in the well.

2. The method of claim 1 , wherein the water-soluble polymer has a molecular weight ranging from about 600,000 to about 1,200,000.

3. The method of claim 1 , where the styrene-butadiene latex is a suspension containing about 45 wt % dry latex.

4. The method of claim 3 , wherein the styrene-butadiene latex contains 70-30 wt % butadiene and 30-70 wt % styrene.

5. The method of claim 3 , wherein the styrene-butadiene latex contains 40-60 wt % butadiene and 60-40 wt % styrene.

6. The method of claim 1 , wherein the water-soluble polymer consists of:
(a) 1-99% by weight of structural units of the formula:

where R 1 is hydrogen or methyl, R 4 is C 1 -C 22 alkylene, R 5 is C 1 -C 22 alkyl or hydrogen, and X is ammonium, lithium, sodium, potassium, an amine or a combination thereof;
(b) 99-1% by weight of structural units of the formula:

where R 1 is hydrogen or methyl, R 2 and R 3 , independently of one another, are hydrogen or C 1 -C 22 alkyl.

7. The method of claim 6 , wherein R2 and R3 are hydrogen.

8. The method of claim 6 , wherein R 4 is a C 2 -C 10 alkylene.

9. The method of claim 1 , wherein the water-soluble polymer is prepared by solution precipitation polymerization in a non-aqueous solvent, or a water-miscible solvent having a low water content, which is a precipitant for the copolymer, so that the dry copolymer is not hydrolyzed.

10. The method of claim 1 , wherein the water-soluble polymer is present at a concentration between about 4 wt % and 8 wt % of dry polymer by weight of dry latex.

11. The method of claim 1 , wherein the concentration of fluid loss agent added to achieve a given American Petroleum Institute (API) fluid loss is about half that required to achieve said fluid loss with the sole addition of latex.

12. The method of claim 1 , wherein the well is subject to gas migration.

13. A method for controlling gas migration in a subterranean well that has at least one gas producing zone, comprising:
(i) preparing a fluid-loss control agent consisting of a single mixture of a styrene-butadiene latex and an unhydrolyzed water-soluble polymer having a molecular weight between 400,000and 2,000,000;
(ii) adding the fluid-loss control agent to a cement slurry comprising cement and water; and
(iii) placing the cement slurry into the well.

14. The method of claim 13 , wherein the water-soluble polymer consists of:
(a) 1-99% by weight of structural units of the formula:

where R 1 is hydrogen or methyl, R 4 is C 1 -C 22 alkylene, R 5 is C 1 -C 22 alkyl or hydrogen, and X is ammonium, lithium, sodium, potassium, an amine or a combination thereof;
(b) 99-1% by weight of structural units of the formula:

where R 1 is hydrogen or methyl, R 2 and R 3 , independently of one another, are hydrogen or C 1 -C 22 alkyl.

15. The method of claim 13 , wherein the styrene-butadiene latex is a suspension containing about 45 wt % dry latex.

16. The method of claim 13 , wherein the water-soluble polymer is present at a concentration between about 4 wt % and 8wt % of dry polymer by weight of dry latex.

17. The method of claim 13 , wherein the concentration of fluid loss agent added to achieve a given American Petroleum Institute (API) fluid loss is about half that required to achieve said fluid loss with the sole addition of latex.

Assignees

• Schlumberger Technology Corp

Inventors

• Michaux Michel
• Drochon Bruno
• Komocki Sylwia

Classifications

• C04B24/163

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C04B24/2652

  Nitrogen containing polymers, e.g. polyacrylamides, polyacrylonitriles · CPC title

• C04B24/2676

  Polystyrenes · CPC title

• C09K8/487 Primary

  Fluid loss control additives; Additives for reducing or preventing circulation loss · CPC title

• E21B33/14

  for cementing casings into boreholes · CPC title