High‐Healing‐Efficiency Dual‐Network Gels for Fractured Formation Plugging

ABSTRACT Gels have been widely utilized as plugging agents due to their excellent deformability and mechanical properties. However, most gel‐based plugging agents fail to fully leverage the benefits of in situ cross‐linked gels and the performance of particle gels. This study proposes a method for preparing acrylic‐based double‐network gels by utilizing hydrophobic associations and metal coordination bonds. The incorporation of a double network structure enhances the mechanical properties of the gel. After a comprehensive performance evaluation, including tensile, rheological, and healing tests, the optimal material (PAA‐Fe 3 ) was selected. The fracture stress of PAA‐Fe 3 reached 193 kPa, with an elongation at break of 2,600% and a healing efficiency of 86.7%. PAA‐Fe 3 , which demonstrated excellent healing performance in 1 wt%–10 wt% NaCl solutions, was formulated as a plugging agent. The PAA‐Fe 3 plugging agent was then tested for secondary plugging, and its plugging mechanism and pressure‐bearing capacity were analyzed. The results show that the PAA‐Fe 3 plugging agent has significant potential for plugging large fractures under medium temperature and high salinity conditions, exhibiting an initial pressure‐bearing capacity of 4.5 MPa for a 1 mm fracture and a secondary pressure‐bearing capacity of 5.5 MPa for a 1 mm fracture under testing conditions of 5 wt% NaCl at 80°C.