Novel Approach to Enhancing Oil-Based Drilling Fluids Properties Using Combined Organoclays

This study investigates synergistic combination of two organoclays (OCs), Claytone-3 and Claytone-II (in equal proportions), to enhance oil-based-drilling-fluid (OBDF) performance under high-pressure-high-temperature (HPHT) conditions. This novel approach was compared against individual OCs (Claytone-3 and Claytone-II) and a commercially available OC (MC-TONE). Detailed characterization using advanced techniques revealed distinct differences in the clay mineralogy and particle morphology of the OCs, contributing to their synergistic effects. OBDF performance was rigorously evaluated by assessing key drilling fluid properties and rheology. The combined OC mixture yielded a 7% average improvement in emulsion stability compared to individual OCs and effectively mitigated sagging under both static and dynamic conditions after aging at 275 °F and 500 psi for 24 h. Hot rolling at 275°F and 500 psi for 16 h resulted in substantial rheological enhancements, a 12% increase in plastic viscosity (PV) and a 50% increase in yield point (YP) with the combined OCs. The YP/PV ratio also improved by 34%. Furthermore, the combined OCs enhanced gel strength (GS) and yielded better filtration properties, with a 7.5% reduction in filtrate volume and a 3% decrease in filter cake thickness during HPHT filtration tests. The enhanced performance is attributed to the synergistic interaction between the two OCs, the differing surface chemistries of the two OCs promote stronger interparticle interactions, resulting in a more robust fluid structure. This novel combination of OCs offers a promising solution for enhancing OBDF performance in demanding HPHT environments, improving wellbore stability, and contributing to more efficient and cost-effective drilling operations.