Transp Porous Med (2014) 101:477–505 DOI 10.1007/s11242-013-0255-6 Thermodynamics, Kinetics, and Hydrodynamics of Mixed Salt Precipitation in Porous Media: Model Development and Parameter Estimation Hossein Safari · Mohammad Jamialahmadi Received: 2 August 2013 / Accepted: 21 November 2013 / Published online: 6 December 2013 © Springer Science+Business Media Dordrecht 2013 Abstract Demands for hydrocarbon production have been increasing in recent years. Today many oilfields around the world are afflicted by the problem of scaling leading to severe formation damage and hampering of petroleum production from hydrocarbon reservoirs. In current study, a mathematical model for prediction of permeability reduction due to scale deposition is developed based on thermodynamics, kinetics, and hydrodynamics of mixed salt precipitation during flow through porous media. Model predictions are compared with sound experimental data for single deposition of barium sulfate and most importantly, for simultaneous precipitation of barium sulfate and strontium sulfate onto rock surface. Owing to high nonlinearity of the proposed model, kinetic parameters embedded in the mathematical model were tuned employing a new approach based on a hybrid algorithm consisting of particle swarm optimization (PSO) technique and pattern search (PS) algorithm. The average absolute deviations ranging from 1.03 to 9.3 % were observed between model forecasts and experimental data which corroborate the suitability and applicability of the model and also confirm the capability of PSO–PS hybrid algorithm as a highly efficient optimization tool. Estimated values for kinetic parameters are also in accordance with collision theory of chemical reactions. Keywords Mixed salt precipitation · Permeability reduction · Mathematical model · Particle swarm optimization · Pattern Search List of symbols l 1 –l 5 Constants a 1,2 Constants a M , a X Activity of cationic and anionic compound, respectively (mol L -1 ) A ∅ Debye–Huckel coefficient A g Total surface area of grains (m 2 ) H. Safari (B ) · M. Jamialahmadi Department of Petroleum Engineering, Petroleum University of Technology, P.O. Box 63431, Ahvaz, Iran e-mail: safari.hossein68@gmail.com 123