Evaluation of the effects of Kaolinite on the efficiency of oil recovery by radioactive-assisted low salinity waterflood: article / Danial Azim Che Aziz ...[et al.]

Recently, extensive researches are being done on low salinity waterflooding (LSW) as a mean to enhance oil recovery. This study focuses on the impact of kaolinite concentration on the oil recovery by means of radioactive assisted LSW. The LSW experiments conducted were divided into two categories. Firstly, 3 sets (A, B, C) of experiment were conducted using sandpack with varying concentration of kaolin clay (5wt%, 10wt% and 15wt%). The second part of the study include, the use of a radiotracer to help evaluate the sandpack condition during LSW. Kerosene were used as the oil phase of the experiment. Varying results were obtained from each sets of experiments most likely due to the difference in method of preparation of the sandpack prior to LSW. Set A and B showed an increase of recovery with increasing kaolinite concentration. Meanwhile set C and the radiotracers discerned no real correlation between an increase in kaolinite concentration. Highest oil recovery was obtained at 85% of OOIP while the lowest was observed at 51% of OOIP. During experimentation, low initial oil saturation was achieved with the kerosene. Water breakthrough occurred much faster in higher concentration kaolinite sandpack. The increase in pH and MIE mechanisms were evaluated based on the pH values and final Mg2+ and Ca2+ concentration of the produced water. The effect of pH increase was only observed in set C experiment. Concentrations of the Mg2+ and Ca2+ showed a decrease as compared to the initial formation water and low salinity brine in all experiments. Radiotracers experiment produced two RTD models associated with the sandpacks. Kaolinite containing sandpack were shown to be best fitted with the Perfect mixer in parallel RTD model, while clean sandpack showed more alignment with the perfect mixer in series with exchange.