Synthetic proppants and monodispersed proppants and methods of making the same

Patent metadata

Field	Value
Publication number	US-9745507-B2
Application number	US-201313952090-A
Country	US
Kind code	B2
Filing date	Jul 26, 2013
Priority date	Aug 1, 2012
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

Synthetic ceramic proppants are described. Proppants having a monodispersity of 3-sigma distribution or lower are also described, including methods to make these proppants and methods of using these proppants.

First claim

What is claimed is:

1. A method of making a sintered ceramic proppant comprising forming a spherical green body core comprising one or more ceramic particulate materials; wherein the sintered ceramic proppant comprises a monodispersity with a 3-sigma distribution, wherein a width of a total distribution of the sintered ceramic proppant is 5% or less of a mean particle size of the sintered ceramic proppant, wherein the 3-sigma distribution is a size distribution of the sintered ceramic proppant; wherein the sintered ceramic proppant comprises a glassy phase, wherein the glassy phase is present in an amount of 15% to 70% based on weight of the sintered ceramic proppant; wherein the sintered ceramic proppant comprises ceramic whiskers, wherein the ceramic whiskers have an average length from 1 micron to 3.5 microns, an average width from 0.1 to 0.3 microns and a whisker length distribution from 0.1 to 5; wherein 90% of the ceramic whiskers have a whisker length that is less than 5 microns, wherein the sintered ceramic proppant comprises a free alpha-alumina content of at least 20 wt % based on the weight of the sintered ceramic proppant; wherein the sintered ceramic proppant comprises an etching weight loss from 15 wt % to 30 wt % based on the weight of the sintered ceramic proppant;
forming, at the same time or afterwards, a green body shell around said green body core, wherein said green body shell comprises at least one ceramic particulate material which results in a green core/shell body;
sintering said green core/shell body, and, during sintering, diffusing at least a portion of said green body core into said green body shell; wherein the diffusing forms the sintered ceramic proppant having a) a central void or a plurality of hollow regions, and b) a shell.

2. The method of claim 1 , wherein said central void or hollow regions comprises at least 1% by volume of the overall volume of the sintered ceramic proppant.

3. The method of claim 1 , wherein said diffusing results in at least 5% by weight of said green body core diffusing into said shell.

4. The method of claim 1 , wherein said diffusing results in at least 10% by weight of said green body core diffusing into said shell.

5. The method of claim 1 , wherein said diffusing results in at least 50% by weight of said green body core diffusing into said shell.

6. The method of claim 1 , wherein the green body shell has a softening temperature that is higher than the softening temperature of the green body core.

7. The method of claim 1 , wherein said green body shell has a softening temperature of at least 100° C. higher than the softening temperature of the green body core.

8. The method of claim 7 , wherein the softening temperature of the green body shell is from about 300° C. to about 400° C. higher than the softening temperature of the green body core.

9. The method of claim 1 , wherein the green body shell has a porosity of at least 10% by volume based on the volume of the green body shell.

10. The method of claim 1 , wherein the green body shell has a porosity of at least 30% by volume based on the volume of the green body shell.

11. The method of claim 1 , wherein said sintered ceramic proppant has at least 10% porosity in the sintered shell.

12. The method of claim 1 , wherein a slurry of the ceramic particulate material has an Ohnesorge Number (Z) of from 1 to 10, wherein the Ohnesorge Number (Z) is a measure of a sprayability of the slurry.

13. The method of claim 1 , wherein a slurry of the ceramic particulate material has an Ohnesorge Number (Z) of from 2 to 10, wherein the Ohnesorge Number (Z) is a measure of a sprayability of the slurry.

14. The method of claim 1 , wherein a slurry of the ceramic particulate material has an Ohnesorge Number (Z) of from 4 to 6, wherein the Ohnesorge Number (Z) is a measure of a sprayability of the slurry.

15. The method of claim 1 , wherein the whiskers or one or more fibers are formed in-situ in said shell during said sintering and as a result of said diffusing.

16. The method of claim 1 , wherein said diffusing of the green body core or portion thereof into the shell results in a gradient of wherein a higher concentration of the core is present closer to the core than to an exterior outer surface of the proppant.

17. The method of claim 1 , wherein said spherical green body, green body shell, or both further comprise at least one nucleating agent.

18. The method of claim 1 , wherein said ceramic particulate materials comprise cordierite, mullite, bauxite, silica, spodumene, silicon oxide, aluminum oxide, sodium oxide, potassium oxide, calcium oxide, zirconium oxide, lithium oxide, iron oxide, spinel, steatite, a silicate, a substituted alumino silicate clay, an inorganic nitride, an inorganic carbide, a non-oxide ceramic or any combination thereof.

19. The method of claim 1 , wherein said ceramic particulate materials comprise one or more sedimentary materials or synthetically produced materials or both.

20. The method of claim 1 , wherein said spherical green body core and said green body shell are in the absence of igneous or metamorphic materials.

21. The plurality of sintered ceramic proppants of claim 1 , wherein said sintered ceramic proppants have less than 1% by weight of proppant of igneous or metamorphic materials.

22. The method of claim 1 , wherein the green body or a portion thereof has a density, as measured by a gas pycnometer, such that the average density (g/cm3) does not alter by more than 1% between the density of the whole green body compared to the density of the crushed green body.

23. The method of claim 22 , wherein the average density changes 0.005% or less.

24. The method of claim 12 , wherein one or more mobile phases are formed in droplets of the slurry that forms the green body and one phase migrates to the surface of the droplet, which causes a multi-phase droplet to form.

25. The method of claim 24 , wherein said multi-phase droplet forms a non-uniform green body of phases.

26. The method of claim 25 , wherein said non-uniform green body of phases diffuses at different rates into said shell with respect to the phases.

27. The method of claim 1 , wherein said green body core comprises at least 50% by weight, based on the weight of the green body core of glassy material, and said green body shell comprises at least 50% crystalline material.

28. The method of claim 1 , wherein said green body core comprises at least 75% by weight, based on the weight of the green body core of glassy material, and said green body shell comprises at least 75% crystalline material.

29. The method of claim 1 , wherein said green body core comprises at least 95% by weight, based on the weight of the green body core of glassy material, and said green body shell comprises at least 95% crystalline material.

30. The method of claim 1 , wherein the particles used to form the green body core are at least 10% smaller in average mean size (d50 size) compared to the mean particle size (d50 size) of the particles that form the green body shell.

31. The method of claim 1 , wherein the particles used to form the green body core are at least 50% smaller in average mean size (d50 size) compared to the mean particle size (d50 size) of the particles that form the green body shell.

32. The method of cl

Assignees

• Halliburton Energy Services Inc

Inventors

• Skala Robert D
• Fang Christopher Y
• Coker Christopher E

Classifications

• C04B35/19

  Alkali metal aluminosilicates, e.g. spodumene · CPC title

• C04B2235/5481

  Monomodal · CPC title

• C04B35/443

  Magnesium aluminate spinel · CPC title

• C04B2235/5445

  submicron sized, i.e. from 0,1 to 1 micron · CPC title

• C04B35/16

  based on silicates other than clay {(zircon C04B35/48)} · CPC title