CO₂ enhanced gas recovery (CO₂-EGR) is a promising technology to extract additional natural gas from depleted reservoirs with storing CO₂ into underground formations. This work conducted CO₂-EGR simulations in a heterogeneous gas reservoir by using isothermal and non-isothermal models and systematically analyzed the effects of various CO₂ injection parameters on natural gas recovery, CO₂ storage, and their comprehensive benefits. The results indicate that the CO₂ injection well should be perforated in the lower position, whose overlaid layers with low permeability hinder the upward migration of CO₂, and the larger natural gas recovery and CO₂ storage can be achieved simultaneously for better comprehensive benefits. The optimal injection rate is 137.29 m³·d⁻¹ to achieve the highest recovery factor of 64.87%. The decrease in injection temperature and the increase in injection pressure are averse to the enhancement of recovery but beneficial to larger CO₂ storage. The comprehensive benefits of natural gas recovery and CO₂ storage are insensitive to the change of injection pressure and temperature, despite that every single one of them is more subjective to injection pressure than temperature. It's hoped that the findings of this work provide some theoretical guidance for the application of CO₂-EGR.

中文翻译：

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非均质天然气储层注入参数对CO2提高采气率影响的模拟

CO ₂增强气体采收率（CO ₂ -EGR）是一种很有前景的技术，可以从枯竭的储层中提取额外的天然气，并将 CO ₂储存到地下地层中。本工作利用等温和非等温模型对非均质气藏进行了CO ₂ -EGR模拟，系统分析了各种CO ₂注入参数对天然气采收率、CO ₂封存及其综合效益的影响。结果表明，CO ₂注入井应在较低位置射孔，其低渗透层覆盖阻碍了CO ₂向上运移，并且可以同时实现更大的天然气回收和CO ₂存储，以获得更好的综合效益。最佳注入量为137.29 m ³ ·d ^-1以实现64.87%的最高采收率。降低注入温度和增加注入压力不利于提高采收率，但有利于更大的CO ₂储存。天然气回收和CO ₂封存的综合效益对注入压力和温度的变化不敏感，尽管它们中的每一个都对注入压力比温度更主观。希望本文的研究结果为CO的应用提供一定的理论指导。₂ -EGR。