Tailoring smart and high-performance drilling fluids with supramolecular materials: Advances in water- and oil-based systems

Drilling fluids must sustain reliable rheology, filtration control, and wellbore stability as drilling progresses into high-pressure/high-temperature (HPHT) and high-salinity environments under tightening discharge and waste-management constraints. This review synthesizes how supramolecular materials—built from reversible non-covalent interactions (e.g., hydrophobic association, hydrogen bonding, and host–guest complexation)—enable “intelligent” additive systems that adapt to downhole stimuli rather than fail irreversibly like many conventional covalent polymers. For water-based drilling fluids, we highlight supramolecular rheology modifiers that retain viscosity in concentrated brines (e.g., reported maintenance of ∼55 mPa·s at 20 × 10⁴ mg/L NaCl) and cyclodextrin-derived architectures that improve high-temperature filtration by in-situ structural transformation. We also summarize self-healing supramolecular gels that provide conformal, resilient sealing for lost-circulation zones. For oil-based systems, we discuss organoclay-free supramolecular rheology modifiers and interfacial self-assembly strategies that strengthen invert-emulsion stability, including demonstrations of high electrical stability (>550 V) and low HTHP fluid loss (∼10 mL) after 240 °C aging in representative organoclay-free formulations. Overall, the evidence indicates that supramolecular design can decouple performance from strict chemical rigidity, enabling multifunctional and potentially more sustainable drilling-fluid systems; remaining barriers include predictability under coupled field variables, long-term stability, and economic scalability.