Light Weight Proppant With Improved Strength And Methods Of Making Same

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 invention further relates to strong, tough, and lightweight glass-ceramic composites that can be used as proppants and for other uses.

Description

[0001]This application claims the benefit under 35 U.S.C. §119(e) of prior U.S. Provisional Patent Application No. 61 / 384,875, filed Sep. 21, 2010, which is incorporated in its entirety by reference herein.BACKGROUND OF THE INVENTION[0002]The present invention relates to methods to make strong, tough, and lightweight whisker-reinforced glass-ceramic composites. The method can involve forming a self-toughening structure generated by viscous reaction sintering of a complex mixture of oxides. The whisker-reinforced glass-ceramic preferably is strong, tough, and / or lightweight. The present invention further relates to strong, tough, and lightweight glass-ceramic composites used as proppants and for other uses including, but not limited to, armor plating, electronic, optical, high-temperature structural materials and applications, as a low dielectric constant substrate material in high-performance packaging applications; or window materials for the mid-infrared range.[0003]The use of cer...

AI Technical Summary

Benefits of technology

The present invention provides a glass ceramic composite with uniform dispersion of small pores having spherical shape and smooth interior pore surface. The invention also introduces a method of producing a ceramic proppant with controlled pore size, size distribution, and pore shape through the use of reactive sintering or pore formers. The resulting proppant has reduced specific gravity while maintaining mechanical and flexural strength.

Problems solved by technology

The fibers can also impede crack initiation and propagation through the matrix material.

Whiskers can provide strengthening in a similar manner, but load transfer to the whiskers by the matrix is more limited because of the limited length and aspect ratio of the whiskers.

Because whiskers are relatively short, they cannot carry as much load compared to the longer fibers.

It is more difficult to take full advantage of the intrinsic strength of whiskers compared to fibers for this reason.

Processes involving dispersion of preformed whiskers in a green body material have been difficult to successfully implement because whiskers have a tendency to agglomerate resulting in non-uniform concentrations of whiskers throughout the green body and ultimately in the ceramic composite.

Non-uniform whisker concentration results in significant variance in the extent of reinforcement and toughening.

After sintering, the presence of these powders can significantly weaken the whiskers' reinforcing abilities.

Conventional proppants exhibit exceptional crush strength but also extreme density.

Sand is low cost and light weight, but low strength; man-made ceramics, mainly bauxite-based ceramics or mullite based ceramics are much stronger than sand, but heavier.

Second, resin-coated sands are “tacky” and thus exhibit reduced “proppant flow-back” relative to conventional sand proppants (e.g. the proppant stays in the formation better).

Third, resin coating typically increases sphericity and roundness thereby reducing flow resistance through the proppant pack.

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