A concept of hydraulic fracturing flowback treatment using electrodialysis reversal

The possibility of desalinated water production from hydraulic fracturing flowback by electrodialysis reversal (EDR) was investigated. To simulate geochemical reactions of hydraulic fracturing fluid with the formation rocks, fluid-gas-rock reaction was performed in autoclave. Next, an EDR of hydraulic fracturing flowback was simulated and the composition of diluate and concentrate was calculated, assuming that maximum possible Langelier Saturation Index (LSI) in a single-pass EDR unit equipped with low residence time variance spacer was +2.3 and maximum gypsum saturation level was 520%. Simulation suggested that the hydraulic fracturing flowback could be desalinated to total dissolved salts (TDS) of 1,352 mg dm^–3 at water recovery of 89.8%, and it could be reused as a hydraulic fracturing fluid. High LSI and CaSO₄ supersaturation indicated that there was a possibility of calcium carbonate and calcium sulfate precipitation from the obtained concentrate.