Calcium carbonate scaling kinetics in oilfield gathering pipelines by using a 1D axial dispersion model

Abstract The dynamic scaling mechanism of calcium carbonate (CaCO3) in pipelines was examined in this work to study the dynamic scaling process in oilfield gathering pipelines. The investigation began by using dynamic scaling analysis equipment to test the fluid flow pattern in a pipeline interior through the pulse tracer method. The average residence time distribution was obtained from this experiment. Then, a 1D dispersion model of scaling fluid was established by considering the constant of the crystallization reaction rate, which was measured by using the electrical conductivity method. Results showed that the average residence time in the pipeline was long when environmental temperature was high and the back-mixing degree was strong. CaCO3 scaling reaction attributed to the first-order reaction and the reaction rate constant at different temperature was acquired in accordance with the principle of chemical reaction kinetics. The conversion rate of CaCO3 scaling reaction inside the pipeline was calculated using a 1D axial dispersion model. By comparing the calculation results with the scaling reaction conversion of the pipeline in practical testing, the average relative error was determined as 12.76%, and the absolute error range was only 1.66–3.26%. This model can accurately predict the dynamic scaling dynamical process of fluid flow in pipelines and provide the necessary basic information for scale prevention and removal treatment in actual construction.