SCALE FORMATION IN POROUS MEDIA AND ITS IMPACT ON OIL RECOVERY

Abstract

The objectives of this study include: (1) investigation of the chemical and thermodynamic mechanisms of scale formation in porous media and its impact on formation damage; (2) development of a model to predict permeability and porosity reduction resulting from scale deposition in porous media; (3) quantification of the impact of scale formation within reservoir on oil recovery and injectivity loss; (4) examining the impact of scale formation on water flooding efficiency in terms of water saturation profiles and evaluating the effect of composite scale formation in porous media on reservoir properties. Scale formation in oil fields has been repeatedly reported as the main issue affecting water flooding projects. Scale formation occurs both in reservoir porous media and within the operation facilities. In porous media, permeability and porosity tend to change because of scale formation. In oil fields, water injection can drop from thousands barrel per day to zero in one day because of scale formation during field operations. Therefore, prediction of scale formation and evaluating its impact on production performance is of vital importance for the oil industry. In this research, scale formation in reservoir porous media and its impact on reservoir performance during water flooding are investigated. First, mineral deposition is studied from a micro scale (pore scale) standpoint and next, the impact of deposition on reservoir performance is studied on a macro scale basis. A robust model is developed to predict permeability damage resulting from scale deposition in porous media. Results indicate that the solubility of minerals and the amount of fluid that is injected into porous media have the most impact on formation damage of a reservoir. In addition, a synthetic field operation is simulated in this work to study the impact of scale formation on injection and production performance during water flooding. The simulation results show that scale formation leads in the loss of injectivity and a reduction in the ultimate oil recovery. Moreover, saturation profiles indicate that scaling issue within reservoir leads in non-ideal displacement for water flooding.