In the quest to maximize oil recovery while minimizing costs and environmental impact, researchers have turned to a novel approach: blending dimethyl ether (DME) with impure CO2. This innovative strategy, detailed in a recent study published in ‘Energies,’ offers a compelling solution to the challenges posed by traditional enhanced oil recovery (EOR) methods.
The study, led by Kwangduk Seo from the Department of Earth Resources and Environmental Engineering at Hanyang University in Seoul, South Korea, explores the use of DME in conjunction with impure CO2 streams. DME, a versatile solvent known for its ability to reduce minimum miscible pressure (MMP) and interfacial tension (IFT), has emerged as a game-changer in the EOR landscape. However, its high cost has limited its widespread adoption. By mixing DME with impure CO2, researchers aim to achieve a more cost-effective and efficient EOR process.
“The key to this approach is finding the right balance between DME content and CO2 purity,” Seo explains. “Our findings indicate that while higher DME content and CO2 purity can enhance oil recovery, the economic benefits are maximized when using lower-purity CO2 streams.”
The study utilized a compositional model to simulate the injection of DME with impure CO2 streams derived from various purification methods, including dehydration, double flash, and distillation. The results showed that lower oil recovery is achieved with higher impurity content in the CO2 stream, lower DME content, and more heterogeneous reservoirs. However, the net present value (NPV) was highest when using the lowest-purity CO2 stream, highlighting the economic advantages of this approach.
One of the most intriguing findings was the impact of reservoir heterogeneity. In homogeneous reservoirs, the NPV was highest for all impure CO2 streams, suggesting that the economic benefits of this method are particularly pronounced in such environments. “This optimization indicates a greater impact on revenue from reduced CO2 purchase cost than on profit loss due to reduced oil recovery by impurities,” Seo notes.
The research also underscores the potential benefits of solvent reuse and carbon capture and storage (CCS) credits. By reusing the solvent and leveraging CCS credits, operators can further enhance the economic feasibility of this method. For instance, with the less expensive dehydration CO2 stream, injection with some DME maximizes economic feasibility even when oil prices are low. For the dehydration CO2 stream, solvent reuse and CO2 credits with oil prices of USD 90, the DME content of 66% has a maximum NPV of USD 853,472, which is 121% of the maximum value of USD 703,712 from the DME content of 20% without solvent reuse and CO2 credits.
This research opens up new avenues for the energy sector, particularly for operators looking to optimize their EOR processes while minimizing costs and environmental impact. By blending DME with impure CO2, companies can achieve a more efficient and cost-effective EOR strategy, paving the way for future developments in the field. The study, published in ‘Energies’, provides a comprehensive analysis of the economic and operational benefits of this approach, offering valuable insights for industry professionals and researchers alike.