Cement compositions with adjustable mechanical properties

Patent metadata

Field	Value
Publication number	US-2019040297-A1
Application number	US-201716075818-A
Country	US
Kind code	A1
Filing date	Feb 2, 2017
Priority date	Feb 5, 2016
Publication date	Feb 7, 2019
Grant date	—

Abstract

Methods for adjusting the mechanical properties of cement systems include preparing a cement slurry containing water, an inorganic cement and at least two minerals. At least one of the minerals has a specific gravity higher than that of the cement at least one of the minerals has a specific gravity lower than that of the cement. The slurry is allowed to harden and form a set cement. The concentrations of the cement and the minerals may be varied such that the slurry has a constant solid volume fraction and a constant Compressive Strength vs. Effective porosity slurry density.

First claim

1 . A method for adjusting mechanical properties of a cement system, comprising:
(i) preparing a cement slurry comprising water, an inorganic cement and least two minerals, wherein at least one of the minerals has a specific gravity lower than the cement and at least one of the minerals has a specific gravity higher than the cement; and (ii) allowing the slurry to harden and form a set cement;
wherein, the concentrations of the cement and the minerals are varied such that the slurry has a constant solid volume fraction and a constant slurry density, and the minerals are inert with respect to the cement.

2 . The method of claim 1 , wherein the solid volume fraction is between 20% and 45%.

3 . The method of claim 1 , wherein the slurry density is between 1440 kg/m 3 and 1970 kg/m 3 .

4 . The method of claim 1 , wherein the minerals comprise metallic iron, hematite, haussmanite, ilmenite, barite, titanium dioxide, aluminum oxide, calcite or quartz or combinations thereof.

5 . The method of claim 1 , wherein the minerals have a median particle size between 1 micrometer and 1 millimeter.

6 . The method of claim 1 , wherein the inorganic cement is present at a concentration between 60% and 95% by volume of solid blend.

7 . The method of claim 1 , wherein the inorganic cement comprises Portland cement, calcium aluminate cement, lime/silica blends, fly ash, blast furnace slag, zeolites, cement kiln dust, geopolymers or chemically bonded phosphate ceramics or combinations thereof.

8 . A method for cementing a subterranean well, comprising:
(i) preparing a cement slurry comprising water, an inorganic cement and least two minerals, wherein at least one of the minerals has a specific gravity lower than the cement and at least one of the minerals has a specific gravity higher than the cement, and the minerals are chemically inert with respect to the cement; (ii) placing the slurry in the well; and (iii) allowing the slurry to harden and form a set cement;
wherein, the concentrations of the cement and the minerals are varied such that the slurry has a constant solid volume fraction and a constant slurry density.

9 . The method of claim 8 , wherein the solid volume fraction is between 20% and 45%.

10 . The method of claim 8 , wherein the slurry density is between 1440 kg/m 3 and 1970 kg/m 3 .

11 . The method of claim 8 , wherein the minerals comprise metallic iron, haussmanite, ilmenite, barite, titanium dioxide, aluminum oxide, calcite or quartz or combinations thereof.

12 . The method of claim 8 , wherein the minerals have a median particle size smaller than 10 micrometers.

13 . The method of claim 8 , wherein the cement is present at a concentration higher than 60 percent by weight of blend.

14 . The method of claim 8 , wherein slurry placement occurs during a primary cementing operation or a remedial cementing operation.

15 . The method of claim 8 , wherein the inorganic cement comprises Portland cement, calcium aluminate cement, lime/silica blends, fly ash, blast furnace slag, zeolites, cement kiln dust, geopolymers or chemically bonded phosphate ceramics or combinations thereof.

Assignees

• Schlumberger Technology Corp

Inventors

• Terrier Cyril
• Guillot Dominique

Classifications

• C09K8/426

  for plugging · CPC title

• C09K8/473 Primary

  Density reducing additives, e.g. for obtaining foamed cement compositions · CPC title

• C09K8/428

  for squeeze cementing, e.g. for repairing · CPC title

• C09K8/48

  Density increasing or weighting additives · CPC title

• C09K8/467

  containing additives for specific purposes · CPC title