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

Reliable prediction of calcium carbonate, CaCO3, scaling fur estimating sca le production oilfield production wells and surface facilities requires bot h thermodynamic models to indicate the tendency for scaling from solution a nd kinetic models to predict the rate of scaling and thus the time required to cause blockage. The application of such models could contribute to fiel d scale management and in the development of more effective treatments of c arbonate scale during oilfield production. The performance of a kinetic mod el for calcium carbonate scaling rate based on the measurements of individu al calcite crystal growth rates is tested against scale deposition in tube blocking experiments using synthetic formation brines under pressure and te mperature levels. The profile of the scale formed on the internal surface o f the tube during the experiments was measured and compared with the predic ted 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 test ed. 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) too l. (C) 2001 Elsevier Science B.V. All rights reserved.