Hydrodynamic Conditions Evaluation for Scale Control Using the Tube Blocking Test

The precipitation and deposition of inorganic salts throughout the oil production chain can compromise flow assurance. Reducing this risk requires continuous monitoring and control of scaling during the production and transport of oil, gas, and produced water. Dynamic efficiency tests based on the Tube Blocking Test (TBT) method are widely used. These tests allow the evaluation of inorganic deposit formation kinetics and the performance of chemical additives, defining the minimum effective concentration to prevent scaling under controlled temperature, pressure, flow rate, velocity, pH, and supersaturation conditions, in a way that represents field operation. In this context, the efficiency of an inorganic scale inhibitor (0 to 10 mg L^-1) was evaluated at 120 °C, pH 6.72, 116 psi, and under different flow rates (5 to 15 mL min^-1) in a brine representative of petroleum production, using the TBT. It was observed that, in the absence of inhibitor, increasing the flow rate raised the particle flux and favored crystal accumulation, thereby reducing the scaling time. In the presence of inhibitor, the behavior depended on the flow regime. At lower flow rates, the longer residence time required a higher inhibitor concentration to prevent particle growth and deposition. Conversely, at higher flow rates, the greater drag forces and shorter contact time hindered particle adhesion, resulting in better inhibitor performance. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) analyses confirmed the predominant formation of barium sulfate with the presence of sodium chloride. It is concluded that inhibitor qualification by TBT must integrate, in a single evaluation, both physicochemical parameters (pH, brine composition) and hydrodynamic parameters (flow rate, velocity, residence time) to provide a realistic assessment of the chemical additive efficiency.