Next-Generation Enhanced and Improved Oil Recovery Methods for Low-Carbon Petroleum Systems: Nanomaterials, CO₂ Utilization, and Digital Optimization

Dear Colleagues,

Improved Oil Recovery (IOR) and Enhanced Oil Recovery (EOR) remain essential for maximizing hydrocarbon extraction from mature and unconventional reservoirs, where primary and secondary methods often leave behind significant residual oil. As easily-accessible resources decline and energy systems face increasing carbon constraints, the industry is transitioning toward integrated, data-driven and low-carbon “next-generation” EOR/IOR strategies. While traditional methods, involving thermal, gas and chemical injection, result in considerable unrecovered hydrocarbon, emerging “smart EOR/IOR” techniques are revolutionizing recovery efficiency, economic viability and environmental sustainability by integrating advanced technologies in materials science, subsurface physics, and digital technologies.

This Special Issue is dedicated to introducing original research articles and review papers on the development and application of “next-generation” EOR/IOR methods, focusing on multi-disciplinary and scalable EOR/IOR innovations as well as emphasizing the integration of molecular-scale design, reservoir-scale processes, and field-scale deployment. Contributions are encouraged from both conventional and unconventional systems, where challenges such as heterogeneity, ultra-low permeability, and complex fracture networks require tailored synergistic solutions.

Key technological pillars of this Special Issue include:

• Application of Artificial Intelligence (AI) and Machine Learning (ML) Algorithms for Reservoir Optimization: AI-driven frameworks, including digital twins, deep learning algorithms and predictive analytics, enable improved reservoir characterization, production forecasting and optimization of injection strategies. ML algorithms support reservoir performance prediction, optimization of well placement and injection strategies, automated screening of EOR/IOR methods, predictive maintenance of critical equipment and infrastructure through operational health monitoring, and real-time operational decision-making under uncertainty.
• Nanotechnology and Hybrid Fluids: Engineered nanomaterials and advanced chemical systems—including functionalized nanoparticles and polyelectrolyte-based formulations—are being developed to alter wettability at the molecular level, reduce interfacial tension, and enhance mobility control. Emphasis is placed on chemical and thermal stability enhancement, transport behaviour, managing reduced chemical consumption, mitigating environmental risks, and performance improvement under harsh reservoir conditions.
• Hybrid and Sustainability-Driven EOR Strategies: Integrated approaches provide synergistic improvements in sweep efficiency while supporting carbon management objectives. These include foam-assisted processes, combined chemical–gas methods, and CO₂-EOR with geological carbon storage, combined with innovative flood patterns that reach the previously uninvaded areas of the reservoir. Emerging concepts such as solar-assisted thermal recovery, microbial EOR, and environmentally-benign chemicals are also of interest.
• Next-Generation EOR: Advanced foams, gels, and cyclic gas injection (e.g., CO₂ huff-n-puff) are being applied to improve conformance and recovery in heterogeneous and tight formations. Special attention is given to Green Chemistry to develop biodegradable surfactants and biosurfactants to reduce adverse environmental concerns, such as wastewater toxicity. Focus is also placed on fracture–matrix interactions, capillary-driven processes, and wettability effects in unconventional reservoirs with ultra-low permeability and complex fracture networks.

Despite challenges such as high initial capital expenditures and complex subsurface interactions, these next-generation technologies are essential for the economic viability of mature fields as well as for fulfilling the global energy needs within a lower-carbon framework. While the traditional EOR/IOR methods often face operational inefficiencies and environmental concerns, the synergistic application of “next-Gen” EOR/IOR methods is expected to push recovery factors significantly beyond the current limits. By bridging advances in materials, data science, and subsurface engineering, this Special Issue aims to highlight innovations that move beyond laboratory concepts toward field-relevant, economically-viable, and lower-carbon recovery solutions.

Dr. Omid Mohammadzadeh
Prof. Dr. Reza Barati
Guest Editors

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• enhanced oil recovery (EOR)
• improved oil recovery (IOR)
• unconventional reservoirs
• nanotechnology
• artificial intelligence
• carbon sequestration
• shale oil
• CO₂ EOR
• CCUS
• nanofluids
• wettability alteration
• digital twins and AI in reservoir engineering
• techno-economic optimization
• mobility and conformance control
• reactive transport in porous media