Self-toughened high-strength proppant and methods of making same

Patent metadata

Field	Value
Publication number	US-9670763-B2
Application number	US-201113009917-A
Country	US
Kind code	B2
Filing date	Jan 20, 2011
Priority date	Jan 29, 2010
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

Methods are described to make strong, tough, and lightweight whisker-reinforced glass-ceramic composites through a self-toughening structure generated by viscous reaction sintering of a complex mixture of oxides. The present invention further relates to strong, tough, and lightweight glass-ceramic composites that can be used as proppants and for other uses.

First claim

What is claimed is:

1. A method for producing a proppant comprising
a. forming a green body on a template from a green body material comprising
i. at least one metal oxide or precursor thereof that forms whiskers in said proppant and as part of said proppant, and
ii. preformed whiskers, wherein the preformed whiskers are not in contact with each other, and
iii. at least two whisker promoters, optionally in the absence of fluorine or fluorine compounds, wherein the whisker promoters are disposed within the template;
reactive sintering said green body under reactive sintering conditions to form a sintered body comprising in-situ whiskers and at least one amorphous phase, wherein the in-situ whiskers comprise anisotropic crystals elongated along a C-axis.

2. The method of claim 1 , wherein said sintered body further comprises at least one non-whisker containing crystalline phase.

3. The method of claim 2 , wherein said non-whisker containing crystalline phase comprises crystalline alumina.

4. The method of claim 3 , wherein said crystalline alumina is in particulate form.

5. The method of claim 1 , wherein said at least one metal oxide comprises a first metal oxide and a second metal oxide, wherein said first metal oxide and said second metal oxide are different from each other.

6. The method of claim 1 , wherein said at least one metal oxide comprises a first metal oxide and a second metal oxide, wherein said first metal oxide and said second metal oxide are different from each other with respect to metal that forms the oxide, and wherein said template is porous or non-porous.

7. The method of claim 1 , wherein said method further comprises forming said green body around a template so as to completely encapsulate said template.

8. The method of claim 6 , wherein said template is a hollow sphere.

9. The method of claim 6 , wherein said reactive sintering at least partially convert said template to a template comprising in-situ whiskers and at least one amorphous phase.

10. The method of claim 9 , wherein concentration of in-situ whiskers in said template is different from concentration of in-situ whiskers in said sintered body that is on said template.

11. The method of claim 1 , wherein said in-situ whiskers comprise mineral or metal oxide in-situ whiskers.

12. A proppant comprising a shell, a template, a sintered body, wherein said sintered body, the shell, and the template comprises in-situ whiskers disposed within said sintered body, the shell, the template, and at least one amorphous phase, wherein the in-situ whiskers comprise anisotropic crystals elongated along a C-axis, wherein concentrations of the in-situ whiskers in the shell and the template are different.

13. The proppant of claim 12 , said proppant further comprising at least one non-whisker containing crystalline phase.

14. The proppant of claim 13 , wherein said non-whisker containing crystalline phase comprises at least one crystalline particulate phase.

15. The proppant of claim 13 , wherein the proppant has the following characteristics:
mullite phase: 5 wt % to 40 wt %
overall crystalline phase: 10 wt % to 75 wt %
overall amorphous phase: 5 wt % to 50 wt %
quartz phase: 0% to 5%
cristobalite phase: 0 wt % to 5 wt %;
all based on the wt % of said proppant.

16. The proppant of claim 12 , wherein said in-situ whiskers are present as an in-situ whisker phase that is a continuous phase.

17. The proppant of claim 12 , wherein said in-situ whiskers are present as an in-situ whisker phase that is a non-continuous phase.

18. The proppant of claim 12 , wherein said in-situ whiskers are uniformly distributed throughout said sintered body.

19. The proppant of claim 12 , wherein in-situ whiskers are present in said sintered body in a three-dimensional non-woven structure.

20. The proppant of claim 12 , wherein said in-situ whiskers have a phase connectivity of 3.

21. The proppant of claim 12 , wherein said in-situ whiskers have a phase connectivity of 2.

22. The proppant of claim 12 , wherein said in-situ whiskers are metal oxide or mineral derived in-situ whiskers.

23. The proppant of claim 12 , wherein said sintered body encapsulates said template.

24. The proppant of claim 23 , wherein said template is a hollow sphere.

25. The proppant of claim 23 , wherein said template comprises in-situ whiskers and at least one amorphous phase.

26. The proppant of claim 25 , wherein said template further comprises at least one non-whisker containing crystalline phase.

27. The proppant of claim 23 , wherein said template comprise in-situ whiskers and at least one amorphous phase wherein concentration of in-situ whiskers in said template is different from concentration of in-situ whiskers in said sintered body that is on said template.

28. The proppant of claim 23 , wherein said template comprise in-situ whiskers and at least one amorphous phase wherein concentration of in-situ whiskers in said template is lower than concentration of in-situ whiskers in said sintered body that is on said template.

29. The proppant of claim 25 , wherein said in-situ whiskers in said template and in said sintered body comprise mineral or metal oxide derived whiskers.

30. The proppant of claim 12 , wherein said proppant has at least one of the following characteristics:
a. an overall diameter of from about 90 microns to about 2,000 microns;
b. a Krumbein sphericity of at least about 0.5 and a roundness of at least about 0.5;
c. a crush strength of about 10 MPa or greater;
d. a specific gravity of from about 1.0 to about 3.0;
e. a porosity of from about 6% to about 40%;
f. at least 90% of proppant pores having a pore size of from about 0.1 μm to about 10 μm, and
g. at least 80% of proppant pores are not in contact with each other.

31. A method to prop open subterranean formation fractures comprising introducing a proppant formulation comprising the proppant of claim 12 into a subterranean formation.

32. A method of treating a subterranean producing zone penetrated by a well bore comprising the steps of:
a. preparing or providing a treating fluid that comprises a fluid, energized fluid, foam, or a gas carrier having the proppant of claim 12 suspended therein, and
b. pumping said treating fluid into said subterranean producing zone whereby said particles are deposited therein.

33. The method of claim 32 , wherein said treating fluid is a fracturing fluid and said particles are deposited in fractures formed in said subterranean producing zone, or wherein said treating fluid is a gravel packing fluid and said particles are deposited in said well bore adjacent to said subterranean producing zone.

34. A method for producing a glass-ceramic composite comprising
a. crushing a siliceous material to a particle size of from about 0.2 microns to about 5.0 microns;
b. forming a green body on a template from a green body material comprising
i. alumina and/or at least one alumina precursor and the crushed siliceous material in a ratio to form mullite whiskers in said glass-ceramic composite, and
ii. a minor amount of mullite whiskers, wherein the mullite whiskers comprise anisotropic crystals elongated along a C-axis, wherein the mullite whiskers are discrete and separate whiskers aligned in one d

Assignees

• Fang Christopher Y
• Xie Yuming
• Chatterjee Dilip K
• Coker Christopher E
• Halliburton Energy Services Inc

Inventors

• Fang Christopher Y
• Xie Yuming
• Chatterjee Dilip K
• Coker Christopher E

Classifications

• C04B2235/6585

  at an oxygen percentage above that of air · CPC title

• C04B2235/3217

  Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina · CPC title

• C04B2235/3275

  Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite · CPC title

• C04B2235/5445

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

• C04B2235/5472

  Bimodal, multi-modal or multi-fraction · CPC title