Performance evaluation of surfactant enhanced nanomaterial as efficient water based mud additive

Abstract

Increasing world’s demand of hydrocarbon and recent exploration into deepwater reservoir or complex formation causes stability and effectiveness of conventional drilling fluids to be affected as it tends to undergo deterioration such as gelation, degradation, and breakdown of polymeric additives under High Pressure and High Temperature (HPHT) condition. The emergence of nanotechnology has promise high efficient drilling fluids as the nanoparticles adopt well with a wide range of operating conditions. Yet, the stability of nanoparticles in aqueous phase still a major concern due to reagglomeration effect even after high mechanical shearing. Applying electrostatic repulsion force in nanofluid believed to increase dispersion stability. Relatively, surfactant based dispersion is preferred where nanosilica as a negatively charged nanoparticle dispersed in an anionic surfactant known as Sodium Dodecyl Sulphate, SDS to increase electrostatic repulsion between negatively charged molecules for higher stability. Thus, this study is aim to investigate the performance of nanoparticle in presence of surfactant in water based mud in comparison with ultrasonic dispersed nanofluid mud and conventional Polyanionic Cellulose, PAC mud. Nanosilica has better filtration properties and been used as fluid loss control additive in various experiments especially in High Pressure and High Temperature environment. The methodology of this study initially focused into stability investigation of surfactant enhanced nanofluid by measuring the zeta potential value followed by performance evaluation of nanosilica drilling fluid in optimum concentration of SDS by analysing rheological and filtration properties in both ambient and HPHT condition. Experimental analysis shows that surfactant enhanced nano drilling fluid shows higher zeta potential value and exhibit higher dispersion and stability compared to non-surfactant nano drilling fluid and PAC mud. Thus, it shows better rheological and filtration properties especially at HPHT compared to conventional mud. Surfactant added nano drilling fluid able to control fluid loss around 20-30%, reduce mud cake thickness about 25% compared to PAC mud in HPHT condition. The completion of this study promised better nano drilling fluid formulation for efficient and smooth drilling operation by reduced rig time and cost involved.