Mohammadreza Bagheri

Gas‐based enhanced oil recovery (EOR) techniques are critical for maximizing hydrocarbon extraction from mature oil reservoirs, extending field productivity beyond primary and secondary recovery methods. This review comprehensively evaluates major gas EOR processes CO ₂ flooding, hydrocarbon gas injection, nitrogen (N ₂ ) injection, and flue‐gas injection focusing on their mechanisms, applications, economic feasibility, and environmental implications. Unlike prior reviews that address individual gas injection techniques, this paper provides an integrated evaluation of the technical, economic, and environmental dimensions of gas‐based EOR, establishing a unified framework for comparing recovery performance, technology readiness levels, and sustainability potential. Gas injection enhances oil recovery through miscible displacement, viscosity reduction, oil swelling, and reservoir pressure maintenance. CO ₂ flooding demonstrates superior recovery efficiency, typically yielding 10%–20% incremental oil recovery beyond secondary recovery, and aligns with carbon capture, utilization, and storage (CCUS) objectives by enabling both enhanced recovery and permanent CO ₂ sequestration. Hydrocarbon gas injection (rich and lean gas) achieves 15%–25% additional recovery in light oil reservoirs but faces economic and recycling challenges, whereas N ₂ and flue‐gas injections yield 5%–15% and 3%–8% incremental recovery, respectively, providing cost‐effective options for pressure maintenance and late‐stage field rejuvenation. Emerging innovations such as foam‐assisted flooding, nanoparticle‐enhanced injection, solvent‐based EOR, and AI‐driven optimization further improve efficiency and reduce operational risks. Overall, this review highlights gas‐based EOR's potential to enhance oil recovery while reducing net emissions, supporting sustainable hydrocarbon production within evolving low‐carbon energy systems.

Achieving global net-zero emissions by 2050 demands integrated and scalable strategies that unite decarbonization technologies across sectors. This review provides a forward-looking synthesis of carbon capture and storage and hydrogen systems, emphasizing their integration through artificial intelligence to enhance operational efficiency, reduce system costs, and accelerate large-scale deployment. While CCS can mitigate up to 95% of industrial CO₂ emissions, and hydrogen, particularly blue hydrogen, offers a versatile low-carbon energy carrier, their co-deployment unlocks synergies in infrastructure, storage, and operational management. Artificial intelligence plays a transformative role in this integration, enabling predictive modeling, anomaly detection, and intelligent control across capture, transport, and storage networks. Drawing on global case studies (e.g., Petra Nova, Northern Lights, Fukushima FH2R, and H21 North of England) and emerging policy frameworks, this study identifies key benefits, technical and regulatory challenges, and innovation trends. A novel contribution of this review lies in its AI-focused roadmap for integrating CCS and hydrogen systems, supported by a detailed analysis of implementation barriers and policy-enabling strategies. By reimagining energy systems through digital optimization and infrastructure synergy, this review outlines a resilient blueprint for the transition to a sustainable, low-carbon future.

As a rapidly evolving technology, carbon capture and storage (CCS) can potentially lower the levels of greenhouse gas emissions from the oil and gas industry. This paper provides a comprehensive review of different aspects of CCS technology, including its key components, the methods and stages of carbon storage, implied environmental effects, and its pros and cons. This paper also investigates the utilization of CCS as an alternative method to water injection into oil reservoirs. It also probes the technical and operational challenges of implementing CCS technology in the oil and gas industry. Additionally, this paper examines the regulatory and policy issues associated with CCS, including incentives and frameworks for promoting the deployment of CCS technology. Finally, in this paper the potential benefits of CCS are discussed, including reducing the carbon footprint of the oil and gas industry, enhancing energy security, and supporting the transition to a low-carbon economy.