Advancing Invert Emulsion Drilling Fluid Performance in High-Pressure and High-Temperature Conditions with a Novel Organoclay Additive

Abstract Oil-based drilling fluids (OBDFs) often face performance degradation under the extreme thermal and pressure conditions encountered during high-pressure and high-temperature (HPHT) drilling. This study investigates Claytone-SF, a newly developed organoclay (OC), as a next-generation rheological modifier capable of enhancing OBDF behavior in such environments. A side-by-side comparison was performed with a standard additive, MC-TONE, using laboratory simulations that mimic HPHT downhole conditions. The evaluation encompassed mineralogical, elemental, and morphological characterization of the OCs using XRD, XRF, SEM, and PSD techniques. The drilling fluids were further subjected to a suite of tests including density measurements, electrical stability analysis, rheological profiling, and filtration performance, all conducted at 275°F and 500 psi. Sag resistance was assessed under both static (vertical and inclined) and dynamic (150°F) conditions. Findings revealed that Claytone-SF significantly enhanced fluid performance. It increased electrical stability by 3% without affecting density, improved sag control in both static and dynamic settings, and elevated key rheological parameters—plastic viscosity rose by 23%, yield point by 40%, and YP/PV ratio by 13%. Additionally, filtration efficiency improved with an 8% decrease in fluid loss and a 12% reduction in filter cake thickness. These results position Claytone-SF as a high-potential additive for OBDF applications in HPHT drilling, enabling improved emulsion integrity, solids suspension, and fluid loss control. Continued optimization and targeted field validation are recommended to extend these laboratory insights to operational deployment.