Enhanced oil recovery by smart water injection in sandstone reservoirs (Malaysian Crude Oil)

Abstract

Recently, the scale of studies on smart water – one of EOR method - has increased. From decades, water flooding is one of the most used methods to increase oil recovery. However, more effective in sandstone reservoirs is injecting low salinity brine. Due to changing wettability, improved oil mobility in pores can be reached. The studies show, that the significant increase of oil recovery might be achieved. Main objective of the project is to answer the question: Can “smart water” be used to enhance oil recovery in Malaysian sandstone reservoirs. Laboratory experiments and field tests show that it can enhance the oil recovery over conventional higher salinity water flooding. Until now, the mechanism behind low salinity water flooding is under consideration for further discussions, but it is generally accepted that low salinity water flooding improves microscopic sweep efficiency by modifying rock wettability. For low salinity condition, it has been suggested that desorption of polar oil components as result of pH increase makes the rock more water-wet. In this project, three core flood experiments will be performed to determine the effect of different water salinities on the oil recovery. Two homogeneous reservoir cores which contain active clays with crude oil which has enough polar organic compounds will be used during the experiments. All experiments were conducted at reservoir temperature, around 100°C. Core flood effluents will be sampled regularly to investigate crude oil-brine-rock interactions by measuring pH, density, and different ions concentration of produced water. Comparison between the results of the three types of water and its effect on the recovery factor will be conducted.