The kinetics of carbonate scaling—application for the prediction of downhole carbonate scaling

Reliable prediction of calcium carbonate, CaCO3, scaling for estimating scale production oilfield production wells and surface facilities requires both thermodynamic models to indicate the tendency for scaling from solution and kinetic models to predict the rate of scaling and thus the time required to cause blockage. The application of such models could contribute to field scale management and in the development of more effective treatments of carbonate scale during oilfield production. The performance of a kinetic model for calcium carbonate scaling rate based on the measurements of individual calcite crystal growth rates is tested against scale deposition in tube blocking experiments using synthetic formation brines under pressure and temperature levels. The profile of the scale formed on the internal surface of the tube during the experiments was measured and compared with the predicted results from the kinetic model. The application of the kinetic model to the prediction of carbonate scaling in a North Sea well has also been tested. The results from the model are in good agreement with the actual scale profile recorded in the tubing by a downhole multi-finger caliper (MFC) tool.