A dynamic method for experimental assessment of scale inhibitor efficiency in oil recovery process by water flooding

Abstract

Scale formation due to the mixing of injection water with formation water causes formation damage and reduction in petroleum production. By using scale inhibitors, scale formation/scaling could be prevented. In this work, static experiments were performed with rapid controlled precipitation tests, which were undertaken using three different scale inhibitors namely Falat scale inhibitor, Scahib 760 scale inhibitor and Scahib 780 scale inhibitor. Results show that parameters such as temperature and pH have significant effects on scale inhibitor efficiency. In this study, at pH of 7.8–9 it was found that an increase in pH can lead to a decrease in SI efficiency. In addition, acquired data shows that Falat scale inhibitor is more efficient at 45 °C but scale inhibitors (Scahib 760, 780) have better efficiencies at 25 °C. SEM tests were performed to find structure deformation and morphology of precipitation crystals, which indicated that scale inhibitor can have various effects on crystal's shapes. Finally, dynamic tests were performed with coreflood equipment that indicated higher recovery by using the scale inhibitors. The dynamic tests results show that the recovery factor in the presence of Scahib 760 scale inhibitor is about 58% and breakthrough time is 2099 (sec). In the absence of scale inhibitor, the recovery factor is about 52% and breakthrough time is 2720 (sec).