NUMERICAL EVALUATION OF SCALE-INHIBITOR DISTRIBUTION IN ANNULAR TWO-PHASE FLOW FOR AN OFFSHORE PRODUCTION PIPELINE

Resumo

This study presents, for the first time in the literature, a numerical investigation of the dispersion of a scale inhibitor, which uses monoethylene glycol (MEG) as a solvent, injected into oil-production pipelines operating under oil–water core-annular flow conditions. The proposed methodology combines 1D simulations with 3D simulations. The prediction of flow conditions such as pressure, temperature, holdup, and flow pattern profiles throughout the production line was performed using the transient 1D multiphase flow simulator ALFAsim. The results of the 1D simulation were used as boundary conditions for 3D simulations performed in ANSYS Fluent to characterize the local multiphase flow near the Chemical Injection Valve (CIV). Four injection scenarios were evaluated based on nominal manufacturer rates and real field-measured rates. The simulations reveal that the injected inhibitor remains confined to the water layer throughout the domain. Near the injection region, its concentration exhibits noticeable spatial variability. Although local fluctuations in the actual flow-rate profiles modify the inhibitor mass-fraction patterns, these variations do not produce meaningful changes in the overall concentration levels along the pipeline. The findings support the design of more effective injection strategies.