Thermo-Regulable Smart Hydrogel for In Situ Deep Leakage Plugging via Cooperative Hydrogen Bonding

Addressing environmental and economic concerns from oil/gas well leakage, this study develops an innovative thermal-regulable smart hydrogel system, fabricated through the synergistic combination of acrylamide (AM) and grafted cellulose nanocrystals (GCNC), which achieves effective in situ leakage plugging without requiring conventional initiators or cross-linking agents. Structural analyses (FTIR/Raman) confirm a stable 3D network formed via N–H···O═C hydrogen bonds. The hydrogel shows exceptional mechanical properties (9522% elongation, 4.0 MPa compressive strength) and enhanced fatigue resistance at optimal GCNC loading. Gelation properties (temperature, time, strength) are precisely tunable via AM/GCNC ratio. The material maintains excellent stability under harsh conditions (high-temperature/salinity) without syneresis. Plugging tests demonstrate superior performance (breakthrough pressure: 13.95–22.74 MPa; gradient: 46.04–75.05 MPa·m–1) at elevated temperatures. This sustainable alternative effectively tackles lost circulation while promoting ecological resource utilization, advancing greener and more efficient oilfield technologies.