| dc.description.abstract | Underbalanced drilling often uses foam because of its superior hole-cleaning capacity, low density, and reduced liquid requirements. However, it must be stable under borehole conditions to function as a drilling fluid. When the foam is unstable, it loses its viscosity, causing the liquid to drain and create slugging flow, causing a temporary overbalance that may damage the formation. This study aims to improve aqueous foam stability using nanoparticles with unique surface properties.
Nanoparticles possess unique properties due to their small size and high specific surface area. Furthermore, their surfaces can be modified to display desired properties. As part of this study, bare (NS1) and functionalized silicon oxide nanoparticles (NS2, and NS3) were studied to improve the stability of aqueous foams. A foam circulating flow loop with horizontal pipe viscometers and a vertical drainage testing cell was used to create foam and analyze its characteristics. Foams with varying nanoparticle concentrations (1 to 3% by wt.) and foam qualities (40 to 60%) were generated at 1000 psi. The rheology and stability of these materials were then investigated. To assess the drainage, the hydrostatic pressure distribution was measured as a function of time after a fully generated foam was trapped in a vertical test cell.
A significant increase in apparent viscosity and reduction in liquid drainage was observed when the baseline foam quality (in-situ gas volumetric concentration) was raised from 40% to 60%. Similar changes in property were also observed in nanoparticles containing foam. In addition to this, experiments showed that nanoparticles have an impact on the properties of foams. With the addition of nanoparticles, foams became more viscous and stable. The type (coating) of nanoparticles also influences their effectiveness. For instance, amino-functionalized silica nanoparticles (NS2) provide better foam stability than regular nanoparticles (NS1) and nanoparticles treated with silane (NS3). | en_US |
