Effectiveness of Colloidal Gas Aphron Fluids Formulated with a Biosurfactant Enhanced by Silica Nanoparticles

Abstract

<p>At-balance drilling technology applications demand the use of special drilling fluids, For example, colloidal-gas-aphron fluids (CGA) are being deployed to good effect in drilling applications. GCA-based drilling fluids have physico-chemical attributes that enable them to usefully influence and control downhole conditions. Furthermore, the involvement of nanoparticles and surfactants in their formulations enhances the performance and stability of CGA suspensions. This study describes the stability analysis, rheological characterization and filtration properties of CGA suspensions for the novel eco-friendly biosurfactant, <i>Olea europaea </i>(common olive), in presence of nanoparticles. Filtration and stability analysis was performed using API filtration tests and the static drain-rate technique, respectively. Several rheological models are developed to quantify the shear-flow characteristics of Olea-nano-based CGA suspensions. The Herschel-Bulkley and the Mizhari-Berk models provided the best shear-flow prediction accuracy with very small error values in terms of root mean squared error. Results reveal that the introduction of the biosurfactant improves the CGA-based fluid properties. Moreover, the observed improvements are further enhanced by including silica and fumed silica nanoparticles in the formulations. The Olea-nano-CGA-based fluids exhibit non-Newtonian behavior. The rheology of CGA-based fluids depends upon base-fluid viscosity, as it does in aqueous polymeric foams. The optimum concentrations of nanoparticles in Olea-nano-based CGA fluids is identified to provide them with fluid-flow indices ranging between 0.15 and 0.30. </p>