Labrador Study and Optimization of Smart Water Flooding in South Carbonate Reservoir

A large part of reservoir rocks is composed of carbonate rocks, which are more complicate. The most important challenge in oil production form the carbonate reservoirs, which decreased the ultimate oil recovery is that a great volume of oil remains in the rock. Enhanced oil recovery (EOR) techniques play an important role in improving oil production. Injecting smart water into the oil reservoir is one of the new methods of increasing oil extraction, which is designed by adjusting and optimizing the composition of ions in the injected water. Smart water injection into oil reservoirs is widely used in the oil industry due to its low cost compared to other methods of EOR. Generally, the objective of this study is better utilization of water flooding methods to increase the oil recovery efficiency from the carbonate reservoirs. Therefore, in this research, the effect of magnesium, sulfate and calcium ion concentrations in the process of enhanced oil recovery by smart water injection method on oil recovery coefficient from carbonate rock is investigated. By comparing the recovery factors for the double-distilled water and water types containing divalent ions, it was found out that the presence of divalent ions has a positive effect on the ultimate recovery from the carbonate reservoirs. In addition, changing the divalent ion concentrations in the designed smart water proved that an increase in the concentration of magnesium, sulfate, and calcium promotes the oil recovery factor. By comparing the final oil recovery coefficient of smart waters 4, 5 and 6 compared to smart water 3, it was found that by increasing of ions concentration of  Mg+2, SO4-2 and Ca+2 increase of the final oil recovery coefficient from 55%, 57.7%, 56% and 59% are in carbonate rocks, respectively. In other words, increasing the concentration of calcium ions had the greatest effect on oil recovery factor and increasing the concentration of sulfate ions had the least effect on the oil recovery factor.