Performance prediction of ion-engineered water injection (EWI) in chalk reservoirs using Response Surface Methodology (RSM)

Abstract

Ion-engineered water injection (EWI) is one of the advantageous enhanced oil recovery (EOR) techniques that gained considerable attention in recent years. Many mechanisms have been proposed for additional oil recovery with modified seawater composition when injected into carbonate formations. However, the prediction of EWI is a big challenge due to complex rock/fluid interactions at pore level and related mechanisms. Thus, an efficient design method for water composition is required. This study investigates the optimization of EWI through the concentration of the active and non-active ions in injection water at laboratory scale for chalk core samples by considering the most dominant design parameters. Data from many imbibition tests of chalk core samples were selected. The Response Surface Methodology (RSM) was used to screen the significant contributing parameters. The sensitivity analysis showed that the four most important design parameters are crude oil acid number (TAN), crude oil base number (TBN), temperature, and injected water salinity. An optimum EWI design was suggested, and the predicted responses were validated using other experimental results that have not been used for model development with high accuracy. The model can be applied for experimental design and optimum water composition.