Diutan as a rheological modifier in sorel cements

Patent metadata

Field	Value
Publication number	US-9771773-B2
Application number	US-201415310737-A
Country	US
Kind code	B2
Filing date	Jun 12, 2014
Priority date	Jun 12, 2014
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

Systems and methods for modifying rheology of a cement slurry are described. Methods may include forming a cement slurry composition and placing the cement slurry composition in a subterranean formation. The cement slurry composition contains water, diutan, and a magnesium oxychloride-based Sorel cement and can have specified properties for a ratio of diutan to water, a thixotropic index value, and a yield point.

First claim

What is claimed is:

1. A method of servicing a wellbore located in a subterranean formation, comprising:
forming a cement slurry composition comprising water, a magnesium oxychloride-based Sorel cement and diutan, wherein the cement slurry composition has:
a ratio of the diutan to the water of about 1 g:100 mL to about 1 g:125 mL,
a thixotropic index value of greater than 2 to about 6.8, and
a yield point of greater than 25 lbs/100 ft 2 to about 83 lbs/100 ft 2 ; and

placing the cement slurry composition in the wellbore located in the subterranean formation.

2. The method of claim 1 , further comprising allowing the cement slurry composition to set in the subterranean formation.

3. The method of claim 1 , wherein the magnesium oxychloride-based Sorel cement comprises magnesium oxide and magnesium chloride in a weight ratio of approximately 1:1.

4. The method of claim 1 , wherein the weight ratio of the diutan to the Sorel cement is about 1:300 to about 1:400.

5. The method of claim 1 , wherein the cement slurry composition is placed in a horizontal wellbore.

6. The method of claim 1 , wherein the cement slurry composition is placed in a vertical wellbore.

7. The method of claim 1 , further comprising mixing the cement slurry composition using mixing equipment.

8. The method of claim 1 , wherein the cement slurry composition is placed in the wellbore using one or more pumps.

9. The method of claim 1 , wherein the magnesium oxychloride-based Sorel cement comprises magnesium oxide and magnesium chloride in a weight ratio of about 2:1 to about 1:2.

10. The method of claim 1 , wherein the cement slurry composition further comprises at least one of a set retarder, a water-resistance enhancing material, or a combination thereof.

11. The method of claim 10 , wherein the cement slurry composition comprises the set retarder, and wherein the set retarder is selected from the group consisting of gluconic acid, tartaric acid, citric acid, sodium tripolyphosphate, sodium hexametaphosphate, and any combination thereof.

Assignees

• Halliburton Energy Services Inc

Inventors

• Reddy B Raghava
• Pascarella Natalie Lynn
• Recio Iii Antonio
• Eoff Larry Steven

Classifications

• C04B24/38 Primary

  Polysaccharides or derivatives thereof {(C04B24/243 takes precedence)} · CPC title

• C04B28/32

  Magnesium oxychloride cements, e.g. Sorel cement · CPC title

• E21B33/14 Primary

  for cementing casings into boreholes · CPC title

• C04B2103/0085

  Thixotropic agents · CPC title

• C09K8/467

  containing additives for specific purposes · CPC title