Cellulose nanofiber-reinforced supramolecular polymer gels for temporary plugging of fractured oil and gas reservoirs.

The development of oil and gas from fractured reservoirs is hindered by reservoir complexity, wellbore instability, lost circulation, and formation fluid intrusion during drilling. Various plugging materials and strategies have been employed; however, physical plugging materials often suffer from mismatched particle and fracture sizes, while chemical plugging materials face challenge with low plugging strength as well as tedious operation conditions. In addition, achieving both high plugging effectiveness during use and superior degradability after service remains a challenge. Supramolecular polymer gels, with their high strength and dynamic tunability, present a promising solution. This study reports the synthesis of a supramolecular polymer gel using acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, divinylbenzene, polyvinyl alcohol, and TEMPO-oxidized cellulose nanofibers (CNFs) through in situ radical polymerization. Due to the formation of covalent bonding and multiple hydrogen bonding, as well as the strong reinforcement and acid degradation capacity of CNFs, the supramolecular polymer gel demonstrates high compressive strength (0.69 MPa at a strain of 75 %), good thermal resistance (120 °C for 30 day), excellent plugging effect (> 11 MPa), and high degradation capacity (~ 94 wt%). This work provides new insights for developing high-strength, high-degradation supramolecular polymer gel as temporary plugging materials, promoting the development of oil and gas from fracturing reservoirs more efficiently and safely.