The effect of surface properties of silicon dioxide nanoparticle in drilling fluid on return permeability

The oil and gas industry faces significant challenges in drilling and completion operations, particularly with respect to formation damage and wellbore instability. One approach to mitigating these issues is the use of nanoparticle-enhanced drilling fluids, which can improve fluid filtration and reduce formation damage. However, the influence of nanoparticle surface properties on these effects is not well understood. Therefore, the aim of this study is to investigate the influence of the zeta potential of nanoparticles in drilling fluids on the filtration of drilling fluids and its effect on the permeability of porous media. The motivation behind this work is to enhance the understanding of the role of nanoparticle surface properties in improving drilling fluid filtration and reducing formation damage. The novelty of this work lies in the exploration of the influence of nanoparticle surface properties on the return permeability of porous media. Silicon dioxides were used to represent the nanoparticles, and the surface was modified by silanization with a carboxyl group. Filtration and permeability alteration were analyzed using return permeability experiments on Berea sandstone cores under overburden pressure, pore pressure, overbalance pressure, and temperatures of 3000 psi (20.68 MPa), 1000 psi (6.89 MPa), 500 psi (3.45 MPa), and 140 °F (60 °C), respectively. Bentonite-free water-based drilling fluid and sodium chloride brine were used to represent the formation fluids. The results show that the addition of non-functionalized SiO2, and low and high carboxyl functionalized SiO2 reduced the filtration by 13%, 33%, and 36%, respectively. Although the addition of nanoparticles into the drilling fluid can reduce fluid invasion into the porous media, solid invasion into the porous media can be detrimental and cannot be easily remediated in recovering return permeability. Return permeability of porous media after exposure to drilling fluids without nanoparticles and with non-functionalized SiO2 decreased by 47% and 82%, respectively. In contrast, exposure to drilling fluid with low and high carboxyl functionalized SiO2 decreased only by 21% and 15%, indicating the importance of nanoparticle surface properties in increasing the return permeability of porous media.