Numerical Simulation of Transient Transport of Scale Inhibitor in an Oil-Water Trunkline with Multiple Flowlines

Abstract Various inorganic scales deposited on the inner wall of production flowlines and transport trunk pipelines in oilfields where the produced saline water is involved cause a lot of flow assurance problems. Therefore, scale inhibitors have been developed and commonly used to prevent or mitigate scale deposition. Effective scale inhibition treatments in trunkline flows of oil-water mixtures depend on the local concentrations of the scale inhibitor along the flow direction. Prediction of the scale inhibitor concentration distributions under transient turbulent flow conditions can provide useful information for monitoring scale inhibition and optimally designing anti-scaling treatments. In this paper, a mathematical model is proposed to describe oil-water two-phase transient turbulent flow in a trunkline system with multiple flowlines. Turbulence effects are taken into account by employing the standard k-s turbulence model. And then a scale inhibitor mass transport model coupling this transient flow is also presented. The Computational Fluid Dynamics (CFD) simulations based on all those models are performed for the trunkline system. The simulated flow velocity and pressure fields, water volume fraction, and scale inhibitor concentration distributions along the trunkline are analyzed. Factors affecting the scale inhibitor concentration distribution are evaluated. The simulations coupling oil-water two-phase transient turbulent flow with mass transport of the scale inhibitor in the trunkline show that flow velocity of the mixture has a great impact on the inhibitor concentration distribution. This paper provides insights into the complex interactions that govern the flow behavior of the scale inhibitor, offering a comprehensive understanding that can aid in optimizing scale inhibition treatment strategies and enhancing the efficiency of pipeline operations.