In the heart of China’s Shengli Oilfield, a groundbreaking study led by Dejun Wu from the Exploration and Development Research Institute is revolutionizing how the energy sector approaches enhanced oil recovery. The research, published in the Journal of Engineering Sciences, delves into the complexities of heterogeneous combination flooding and its impact on remaining oil extraction in varying reservoir types. This isn’t just about incremental gains; it’s about redefining what’s possible in the quest for more efficient and effective oil production.
Wu and his team tackled a significant challenge in the Ng3 block of the Gudao Oilfield. The formation’s heterogeneity, combined with varied well network deployments and chemical agent injection volumes, made it difficult to optimize oil extraction. “The key,” Wu explains, “is understanding how different balanced displacement methods interact with the unique characteristics of each reservoir type.” The study used reservoir numerical simulations to create five distinct models, each mimicking real-world conditions.
The findings are compelling. For reservoirs with developed high-permeability zones, heterogeneous combination flooding creates advantageous water flow channels. However, well network infilling can significantly boost the swept volume in low-permeability areas, enhancing displacement efficiency. “In these scenarios,” Wu notes, “the balanced displacement effect of well network adjustment can be more pronounced than that of heterogeneous combination flooding alone.”
In reservoirs with imperfect injection-production well networks, the story changes. Improving the well network increases the sweep range of streamlines, and synergistic heterogeneous combination flooding dynamically regulates and strengthens remaining oil extraction. Here, well network adjustment outperforms heterogeneous combination flooding. “This dynamic regulation is crucial,” Wu emphasizes, “as it allows for real-time adjustments based on reservoir conditions.”
The study also sheds light on unconnected reservoirs and rhythmic reservoirs. In unconnected reservoirs, well network adjustment effectively overcomes fault-blocking effects, extracting otherwise inaccessible remaining oil. In rhythmic reservoirs, heterogeneous combination flooding plugs high-permeability water-flooded intervals, increasing water absorption in low-permeability zones and extracting high-saturation remaining oil.
For interbed reservoirs, layered water injection significantly improves vertical water absorption imbalance. Heterogeneous combination flooding further enhances conformance control and oil displacement at different layers, improving sweep efficiency and oil displacement. Wu highlights that “layered allocation of heterogeneous combination flooding can achieve vertical balanced displacement to the maximum extent.”
This research isn’t just about scientific curiosity; it has profound commercial implications. By optimizing oil extraction methods tailored to specific reservoir types, energy companies can significantly boost production and reduce operational costs. The insights provided by Wu and his team offer a roadmap for future developments in the field, guiding the energy sector toward more efficient and sustainable practices.
As the energy sector navigates the complexities of enhanced oil recovery, this research from the Exploration and Development Research Institute serves as a beacon, illuminating the path toward more effective and efficient oil extraction methods. The findings, published in the Journal of Engineering Sciences, underscore the importance of tailored approaches in heterogeneous combination flooding, paving the way for innovative solutions in the ever-evolving energy landscape.