Designing novel fly ash proppant with high buoyancy and high durability for hydraulic fracturing: an experimental investigation

Proppants are essential components in hydraulic fracturing, ensuring that fractures maintain conductivity. In high-pressure, harsh environments, high-strength, durable proppants are used, which are expensive and require costly fracture fluids. This research evaluates the ability to develop a new type of proppant using fly ash, a waste material, and assess the proppant’s durability under harsh conditions. Fly ash-based proppant is durable, environmentally friendly, buoyant, and cost-effective. To develop the fly ash-based proppant, an alkaline solution was used as an activator and binder. The proppant samples were tested under high temperature and pressure, as well as in acidic, alkaline, saline, and crude oil environments to evaluate their durability. Density was also assessed to determine the buoyancy of the proppant, which affects the fracturing fluid. The mix designs included weight ratios of 20%, 22%, and 25% binder, with a fixed 25% water content in all mixtures. After environmental testing, the B20W25 mix design was the best performing, showing minor erosion and deterioration. Conversely, the increasing binder concentration in the mix did not withstand the more aggressive environmental conditions. The density of the samples ranged from 1.33 to 1.36 g/cc, making them lighter than sand and thus highly buoyant.