9:45 AM - 10:00 AM
[STT17-04] The role of physical and chemical processes of silica scale growth in geothermal wells
Keywords:Silica scaling, Geothermal, Simulation
The meso-scale approach is to investigate the motion of individual colloidal silica particles near the pipe wall with particle-wall interaction using Lagrangian method, while in macro-scale, we use a lattice Boltzmann method to model flow and solute-transport and use the scheme of building up silica scale. The meso-scale model is deployed to derive the deposition rate of colloidal silica, which is used for silica scale growth in macro-scale simulation. We then compare the amount of silica scale precipitation estimated from our simulation estimated with that of the observed both from laboratory experiments and from field observations.
Our results indicate that our simulation gives more realistic silica scaling qualitatively and quantitatively than the existing methods using only reaction kinetics. We conclude that the shear flow rate, which is closely related to the transport process of colloidal silica, is the one of the dominant factor, and that the hydrodynamic process needs to be taken into account to control the silica scaling.