Case Study: Strategies for Controlling the Performance of Slow-Release Scale Inhibitors From Completion to Production

_ Inorganic scale deposition is a ubiquitous challenge in oilfield operations due to the confluence of complex water chemistry and widely varying process conditions. When conditions become favorable, scale formation can be rapid, extensive, and lead to costly impacts to production (Kamal 2018). Given this risk, it is common practice for well operators to include scale inhibitors in their production chemistry treatment packages (Olajaire 2015). The most common types of inhibitors are organophosphonates, anionic low-molecular-weight polymers, or combinations thereof. Mechanistically, scale inhibitors function by inhibiting the nucleation of scale crystals, retarding growth of the crystals as they form, or preventing deposition of precipitated solids onto downhole surfaces (SPE 87470). Benefits of Slow Release Most inhibitors are applied as liquids via either continuous, batch, or squeeze treatments (Kan 2020), but another option is to use a slow-release solid scale inhibitor. A variety of different options have been developed and tested over the years (SPE 134414; SPE 199255), and new approaches continue to be reported (Xiao 2024; Wu 2025). Broadly speaking, these products are designed to provide extended periods of protection against scale deposition by slowly releasing an active inhibitor molecule into the well. The active molecules, mechanisms of retention and release, and timescales of protection vary widely and as such, one solid scale inhibitor may not be interchangeable with another. Operators should carefully consider the characteristics and properties of the products they are considering to ensure they are compatible with the downhole environments being treated. Incorrect application may not only fail to achieve the desired scale-inhibition behavior, but also negatively impact well performance through additional formation damage and solids deposition. Finoric has developed a family of slow-release solid scale inhibitors under the tradename of ScaleGone. Two versions of the product are currently available (Fig. 1), and additional variations are under development. The base version contains a slow-dissolving active ingredient that is encapsulated by an inert polymer material; the polymer coating provides an additional barrier between the active ingredient and the fluids in the wellbore. A second version contains the same slow-dissolving active ingredient, but does not have a polymer coating. Both formulations comprise high concentrations of the active scale-inhibiting ingredients, but the absence of the polymer coating in the uncoated version affords an even higher level of activity for that product. While the encapsulated formulation has an activity level of approximately 85%, the uncoated formulation has an activity level of nearly 95%. High levels of activity are desirable because they lead to reduced dosage requirements to achieve a target scale-inhibitor concentration in the fluid. Both products are sized to approximately 14/40 mesh so that they blend well with the proppants used during unconventional well completions.