The Use of Fly Ash as a Fracking Fluid and Proppant: Progress to Date.

Work on the application of fly ash in oil and gas production is ongoing. Since the first successful frack was conducted in Southeastern Texas on the Pilosa No. 3 well over ten years ago, more than 100 new and refrack jobs have been successfully completed in both vertical and horizontal wells across more than 20 different formations, encompassing a wide range of lithotypes. In May 2025, the pioneer in this effort, Enhanced Solution Services, along with its intellectual property licensed from the University of Kentucky, was acquired by Superior Energy Services, a large global oilfield technology company. Since then, projects have been initiated in the Middle East, South America, Africa, and most energy-producing areas in the United States. The key to this success is the remarkable rheological properties of fly ash, which exhibit low viscosity and low yield points (high fluidity) and remain stable at very high loadings, up to 5 times those of conventional fracking media. These properties enable fluid transport at low pumping rates over long distances without phase separation. Additionally, high loadings greatly reduce water requirements, as does the use of oilfield brines and formation water in its formulation and the proppant sizes allow it to penetrate and create connectivity within the micro fractures that greatly enhances the stimulated rock volume in the reservoirs. Ultimately, this application addresses the major drawback of hydraulic fracking: the steep production declines observed in many of these wells.