Diminishing capacity of non-hazardous disposal wells injecting under pressure may be related to the water quality and treatment of injectate fluid. Understanding how scale forms can help formulate a plan for treating the well. Temperature and pressure fluctuations can have an impact on solubility coefficients, and can also cause local fluctuations in the equilibrium ion concentration in the solution. Once the seed crystals start growing, the heterogeneous nucleation process may start at surface defects such as joints, seams, or areas with surface roughness. A high degree of turbulence can also start the process of scale deposition, such as restrictions in the well. This presentation focuses on why and where scale forms in a groundwater treatment and disposal system and how to prevent it, which will assist to avoid costly workovers and inefficiencies in chemical dosing.
By Chad Milligan, P.G. and Nicole Franken, E.I.T., SCS Engineers