Thermo-responsive temporary plugging agent based on multiphase transitional supramolecular gel

Abstract

In this study, a thermo-responsive temporary plugging agent was developed with the property of sol-gel-sol transition behavior at different temperatures. At low temperature, the material is in 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 non-covalent interactions between the components, which play an important role for the supramolecular gel formation. These findings provide this system can be applied as temporary plugging agent by the idea of temperature-induced smart material with the specialty of cross-linker and gel-breaker free. Physical simulation experiment results showed that the material is good mobility liquid at room temperature. After injecting to formation, the fluid gradually transformed to hard gel around 90°C with sufficient strength to block cracks. Upon further heating by formation, the hard gel would collapse to sol around 110°C without adding additional gel breakers, leading to flowback sufficiently and low damage to fracture. This novel temporary plugging agent also has potential use in diverting fracturing, network fracturing, drilling, well completion, well clean etc.