Continuous-flow evaluation of Barium Sulfate scale dissolution by integrated spectroscopic and hydrodynamic monitoring

The deposition of barium sulfate (BaSO4) scale remains a critical operational issue in oil and gas production systems, often requiring chemical removal with chelating agents such as ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA). While most dissolution studies are performed in batch mode, continuous-flow systems provide improved control of hydrodynamics, better representing real well conditions. In this work an integrated continuous-flow methodology that couples in-line ATR-FTIR monitoring with simultaneous pressure measurement to evaluate BaSO4 dissolution and permeability recovery in real-time is presented. Experiments conducted using BaSO4-packed bed stainless-steel columns demonstrated the combined spectroscopic and hydrodynamic data reveal a progressive decoupling between chemical dissolution and permeability restoration, driven by the formation of preferential flow pathways that limit sustained fluid-solid contact. DTPA consistently exhibited faster permeability recovery and higher apparent dissolution under flow and the proposed continuous-flow method as able to quantitatively distinguish the efficiency of DTPA and EDTA solutions (0.125 mol·L−1) at 60 °C. This approach provides a reproducible and non-invasive real-time evaluation of scale dissolvers by capturing the dynamic interplay between dissolution chemistry and transport phenomena. This behavior, inaccessible to batch experiments, highlights the importance of functional performance metrics beyond endpoint conversion and establishes a foundation for future automated screening and kinetic studies of scale removal processes relevant for industrial operations. A novel flow method allows real-time monitoring of scale removal using simultaneous infrared spectroscopy and pressure measurements. The approach integrates chemical dissolution kinetics with hydrodynamic effects for more accurate scale-removal assessment. The experimental setup supports automated testing of future dissolvers under realistic flow conditions.