Asphaltene Precipitation can lead to solid particle build-up and deposition that restrict fluid flow. The presence of precipitated solids in the oil can also change the fluid properties, such as viscosity. Particle build-up is usually significant at low fluid flow rate and depends on the geometry of the flow line; for example, build-up can occur in situations where there are constrictions and expansions in the flow line. Deposition is generally affected by fluid flow rate, fluid properties (such as density, viscosity), type of solid precipitated, and adsorption of precipitated particles on to the metal surface or already deposited layer. Overall, precipitation is the first step leading to solids build-up and deposition.