Rigorous modeling of permeability impairment due to inorganic scale deposition in porous media

Water flooding technique has widely been applied in oilfields aiming to augment the natural energy of the reservoir and displace the oil toward production wells. Deposition and accumulation of scaling minerals may occur in oilfields due to the incompatibility existing between foreign fluids injected into the medium and indigenous formation water. Deposition of these minerals in porous media may lead to severe permeability loss, formation damage and hydrocarbon production decline. This paper describes a modeling study representing permeability reduction due to scale deposition by employing an approach based on Least Squares Support Vector Machine (LSSVM) and Coupled Simulated Annealing (CSA), generally referred to as CSA-LSSVM. To this end, almost 1306 experimental data were assembled from the literature aiming to build a comprehensive and reliable model. Applicability of the CSA-LSSVM model was then evaluated in the range of data employed in this study and well accordance was observed between model predictions and experimental measurements yielding an overall correlation coefficient (R-2) 0.999. At the end, permeability reduction data gathered from the literature were analyzed for outlier diagnosis using the leverage statistical algorithm along with providing full details of the implemented method. (C) 2015 Elsevier B.V. All rights reserved.