Advances in gas injection for gas condensate reservoirs: Mechanisms and challenges

Natural gas is a vital energy resource recognized for its cleaner combustion compared to other fossil fuels. A significant proportion of natural gas reserves are gas condensate reservoirs, which exhibit unique thermodynamic behaviors leading to production losses and the retention of valuable hydrocarbons in porous media. Gas injection has emerged as a reliable and environmentally beneficial strategy to enhance recovery from these reservoirs by maintaining pressure and promoting condensate re-vaporization. This review offers a comprehensive analysis of gas injection technologies, including miscible gas injection, Huff-n-Puff, CO₂ injection, and mixed gas injection, customized to various reservoir conditions. The review highlights Huff-n-Puff as a promising method for mitigating condensate blockage during early production, discusses nitrogen injection as a cost-effective and environmentally safer alternative to CO₂ and dry gas, and outlines the key challenges of CO₂ injection, including transport in supercritical form, economic feasibility, and leakage risks. Key contributions of this work include an in-depth discussion of active recovery mechanisms, such as molecular diffusion, bulk convection, and re-vaporization, alongside systematic descriptions of laboratory testing methods for gas condensate characterization. The review also categorizes advancements in modeling, simulation, and experimental studies, highlighting their role in addressing both technical and practical challenges. Furthermore, it explores field applications, environmental impacts, and economic considerations of gas injection, offering insights into sustainable recovery practices. By consolidating global data, field experiences, and recovery techniques, this study identifies critical gaps in current knowledge and provides a framework for optimizing gas injection in gas condensate reservoirs.