Thermo-responsive Temporary Plugging Agent Based on Multiple Phase Transition Supramolecular Gel

In this study, a thermo-responsive temporary plugging agent was developed with the property of solution (sol)–gel–sol transition behavior at different temperatures. At low temperature, the material is in the sol state, while increasing temperature led to a stable gel formation, but the gel can transform to sol again upon further heating. This unique behavior was characterized by a series of SEM, FT-IR, XRD, rheology, and viscoelasticity measurements. All scientific results showed noncovalent interactions between the components, which play an important role for the supramolecular gel formation. These findings provide that this system can be applied as a temporary plugging agent by the idea of temperature-induced smart material with the advantages of cross-linker and gel-breaker free. Physical simulation experiment results showed that the material is a solid free fluid with good fluidity at room temperature. After injecting to formation, the fluid gradually transformed to a hard gel around 90 °C with sufficient strength to block cracks. Upon further heating by formation, the hard gel would collapse to a sol around 110 °C without adding additional gel breakers, leading to the flow conductivity restoring of fractures. This novel temporary plugging agent has potential use in diverting fracturing, network fracturing, drilling, well completion, well cleaning, etc.