Clay nanoparticles modified drilling fluids for drilling of deep hydrocarbon wells

Projections of continued growth in hydrocarbon demand are driving the oil and gas industries to explore new or under-explored areas that are often challenging. Oman, being an oil reliant country, is also striving to go deep for exploration of non-conventional and deep lying oil reserves, as most of the existing fields are approaching maturity. Deep drilling poses a great challenge as the current performance of drilling fluids deteriorate due to high temperature and pressure (HPHT) conditions faced during extended reach drilling operations. Keeping in view the decisiveness of drilling fluids' impact on drilling efficiency, this work presents an approach to stabilize the drilling fluid rheology in HPHT conditions by making use of nanoparticles. Abundantly available in Oman, palygorskite (Pal) (natural hydrous clay mineral with fibrous rod-like microstructure) was purified, synthesized, characterized, functionalized, and tested for the first time in nano-form (10-20 nm diameter) for its effectiveness to tailor the rheology of drilling fluids swiftly. The nanoparticles are able to retain the properties over a wide range of operating temperatures and pressure, thus ensuring efficient operation in versatile formations and operating conditions. After successive laboratory investigations, an absolute proportion of water, regular montmorillonite (Mt), and Pal nanoparticles provided consistent results at various temperatures and pressures, i.e., stable drilling fluid rheology at HPHT environment. The best-recorded results are reported in this paper and the properties focused here are the plastic viscosity, yield point, gel strength, density, shear thinning, spurt lost, fluid lost, and Lubricity index.