Toward Sustainable Fracturing: An Integrated Framework for Produced Water Management in the Ordos Basin
Abstract
To achieve high-efficiency development in the Ordos Basin gas fields, the established main fracturing methodology—characterized by dense fracture spacing, high-rate injection, high-intensity proppant loading, and multi-scale proppant distribution—has significantly enhanced well productivity. However, this approach has concurrently led to a sharp increase in freshwater consumption, creating a pronounced conflict with the abundant availability of unconventional water sources such as produced water. Under the strategic requirements of ecological protection and high-quality development in the Yellow River Basin, the efficient utilization of non-freshwater resources has become an essential pathway toward achieving environmentally sustainable and green development in these gas fields. Comprehensive analysis of produced water characteristics and formation compatibility identified iron ions, suspended solids, and calcium/magnesium ions as key contributors to formation damage. A tailored water treatment strategy was thus established, focusing on the removal of suspended solids and iron ions with supplementary hardness control (Fe2+/3+<10 ppm, Ca2+/Mg2+<2000 ppm). Key technological innovations include an efficient micro‑bubble softening process based on CO2–NaOH synergy for scale inhibition, and a high‑performance salt‑tolerant dry polymer with rapid dissolution (<2 min) and salinity resistance up to 88,000 mg/L TDS, enabling stable fracturing fluid formulation. Field implementation was optimized through a logistics model featuring intra‑block produced‑water transport and intra‑pad flowback‑fluid recycling. The system has been successfully applied in 138 wells, achieving a cumulative recycled water volume of 62,000 m3 and an average reuse rate of 53%. Field results confirm stable fracturing fluid performance, and post‑fracturing gas tests show comparable productivity to offset wells using conventional freshwater. This work establishes a practical technical framework—from water assessment and treatment to fluid design and field execution—offering a scalable solution for the economic and sustainable use of non‑freshwater resources in tight gas reservoirs.