Influence of inorganic ions in recycled produced water on gel-based hydraulic fracturing fluid viscosity

摘要

In an effort to determine impacts of the increased use of treated produced water in new fracs, the rheology of two fracturing fluids was observed for varying water qualities. Specific ions of interest were spiked at varying concentrations into tap water that was used as a base for the fluids. Apparent viscosities were measured using a Chandler 5500 viscometer once fluids were formulated. Empirically, it was determined that at the chosen concentrations for this study, aluminum, iron, phosphorous, potassium, and sodium all have negative impacts on fracturing fluid stability. Calcium and magnesium improved fluid stability until a critical concentration was reached, resulting in lowered viscosities and a less stable fluid. The carboxymethyl cellulose (CMC) fluid was more resilient to aluminum, potassium, and sodium, and other ions that negatively impacted stability than the guar based fluid. The guar based fluid also benefited from divalent cations more than the CMC fluid. The effect of using concentrated gel hydrated with fresh water and then diluted with concentrated ion solutions was also evaluated and did not show any improvement in fluid stability.