Beneficial Reuse of Coal Combustion Ash Project

The specific objective of this research is the development and commercial deployment of coal fly ash micro-proppants for oil and gas production from fracking. Fracking requires the fracturing of shale, siltstone, or limestone followed by the treatment of the wells to stabilize the fractures. This last step is accomplished by pumping a slurry of natural or manufactured sand into the fractures to prop them open. Hence the term “proppant”. Laboratory work to date indicates that fly ash derived proppants are strong, stable, inert and smooth, capable of creating a “micro” proppant with small particle sizes needed to prop small micro fractures. Both fresh and landfilled fly ash was beneficiated to provide enhanced hydraulic conductivity necessary for product flow back. Field trials of fly ash proppants using Métis Liquid frac technology have produced highly stable liquid proppant slurries capable of being pumped long distances at relatively low pressure without the need for viscosity modifiers. Results demonstrate that fly ash proppants successfully prop very small micro fractures that produce the bulk of the oil gas resulting in enhanced production. Re-fracking old oil and gas wells demonstrated restoration of original production levels, at lower costs than conventional proppants, with new frac jobs showing promise as well. This research will move the technology from the demonstration level to full commercial viability by extending the range of useable fly ash. Fly ash will be tailored to this application by modifying particle size and density gradation to produce better flow dynamics and improve proppant slurry stability and emplacement. Proppants represent a high value market with the potential of consuming millions of tons per year of fly ash, while producing a superior product that results in enhanced oil and gas yields, longer well life, and reduced environmental impact.