In the quest to maximize oil recovery from carbonate reservoirs, researchers have been exploring innovative methods to enhance oil recovery (EOR). One such method, low salinity polymer flooding (LSPF), combines the benefits of smart water and polymer flooding. A recent study led by Seyed Masoud Ghalamizade Elyaderani from the Department of Petroleum Engineering at Tarbiat Modares University in Tehran, Iran, has shed new light on the intricate dance of potential determining ions in this process.
The study, published in Petroleum, delves into the behavior of sulfonated polyacrylamide (SPAM) polymer in the presence of divalent ions, such as magnesium (Mg2+) and sulfate (SO42-), in carbonate reservoirs. The findings reveal that these ions play a pivotal role in determining the polymer’s performance, which could significantly impact the commercial viability of EOR projects.
One of the key findings is the influence of Mg2+ on wettability alteration. “Among divalent anions and cations, only excess amounts of Mg2+ in a smart water-polymer solution could alter the wettability from oil-wet to neutral-wet,” Ghalamizade Elyaderani explains. This shift in wettability is crucial for improving oil recovery, as it helps to displace oil more effectively from the rock surface. The study also found that Mg2+ enhances SPAM adsorption onto carbonate surfaces, further boosting oil recovery. In contrast, excess SO42- impeded interactions between the polymer and the rock, reducing adsorption.
The research also highlights the complex relationship between divalent ions and solution viscosity. At lower SPAM concentrations, excess divalent ions increased solution viscosity due to the shielding effect. However, at higher concentrations, only SO42- improved viscosity, while Ca2+ and Mg2+ reduced it. This viscosity enhancement is critical for maintaining the polymer’s effectiveness in displacing oil from the reservoir.
The study’s findings have significant commercial implications for the energy sector. By understanding and optimizing the role of potential determining ions, oil companies can enhance the effectiveness of their EOR projects, leading to increased oil recovery and improved economic returns. This could be particularly beneficial for mature fields where traditional recovery methods have reached their limits.
The research also opens up new avenues for future developments in the field. For instance, further studies could explore the use of other potential determining ions or combinations of ions to achieve even greater enhancements in oil recovery. Additionally, the findings could inform the development of new polymer formulations tailored to specific reservoir conditions.
As the energy sector continues to seek innovative solutions for maximizing oil recovery, this research provides valuable insights into the complex interplay of potential determining ions in smart water-polymer solutions. By harnessing this knowledge, the industry can move closer to unlocking the full potential of carbonate reservoirs.
