An improved predictive correlation for the induction time of CaCO3 scale formation during flow in porous media.

The induction time, tind, of calcium carbonate precipitation in porous rocks was experimentally measured under dynamic conditions at temperatures from 25 to 120 degrees C with the use of a radiotracer technique, where the gamma-emitting nuclide 47Ca was used as a tracer in order to monitor the scale deposition at real time. Based upon nucleation theory and experimental observations, the following improved correlation is proposed: This equation predicts satisfactorily the induction time of calcium carbonate scale formation under specific dynamic (flow) conditions in the near-well region (T is the absolute temperature in K, and SI is the saturation index, SI=logSR, where SR is the saturation ratio).