This life cycle analysis (LCA) evaluates life cycle greenhouse gas (GHG) emissions associated with a system that produces both natural gas and crude oil. Two systems are defined: System 1, which independently produces natural gas and oil, and System 2, which captures carbon dioxide (CO₂) from the natural gas-processing plant and utilizes this captured CO₂ for enhanced oil recovery (EOR). The LCA uses customized spreadsheet models with emission factors from peer-reviewed literature and publications of the National Energy Technology Laboratory of the U.S. Department of Energy. The modeling results show that the CO₂ EOR scenario using captured CO₂ produces both natural gas and oil with lower life cycle GHG emissions than alternative systems producing natural gas and oil independently. Sensitivity analyses show that the model results are most sensitive to the fraction of CO₂ captured (or equivalently, the fraction of CO₂ vented) at the natural gas-processing facility and the incremental oil recovery factor and net CO₂ utilization factor of the EOR operations. The input variable driving the relative difference in life cycle GHG emissions between these two systems is the fraction of CO₂ captured at the natural gas-processing facility (i.e., the capture rate). The results of this study highlight the necessity of linking processes in the life cycle modeling, as a change to one process can affect other processes within the coupled energy system comprised of natural gas and oil. In addition, this analysis shows, as prior work has also suggested, that CO₂ EOR using captured anthropogenic CO₂ provides a viable means for offsetting carbon emissions from oil production and combustion via the associated storage of CO₂ that occurs incidentally during this tertiary method of oil recovery.

该生命周期分析（LCA）评估与生产天然气和原油的系统相关的生命周期温室气体（GHG）排放。定义了两个系统：系统1，可独立生产天然气和石油；系统2，其从天然气加工厂捕获二氧化碳（CO ₂），并利用捕获的CO ₂来提高采油率（EOR）。LCA使用来自排放源的定制电子表格模型，这些模型来自同行评审的文献以及美国能源部国家能源技术实验室的出版物。建模结果表明，使用捕获的CO _2进行CO ₂ EOR情景与单独生产天然气和石油的替代系统相比，生产天然气和石油的生命周期温室气体排放量更低。敏感性分析表明，模型结果对天然气处理设施捕获的CO ₂分数（或等效地，排出的CO ₂分数）以及EOR的增量采油率和净CO ₂利用率最敏感操作。驱动这两个系统之间生命周期GHG排放量相对差异的输入变量是CO ₂的分数在天然气处理设施中捕获的量（即捕获率）。这项研究的结果突显了在生命周期建模中链接过程的必要性，因为对一个过程的更改可能会影响由天然气和石油组成的耦合能源系统中的其他过程。此外，该分析表明，正如先前的工作所表明的那样，使用捕获的人为CO ₂进行的CO ₂ EOR提供了一种可行的方法，可通过这种第三方法偶然发生的相关联的CO ₂储存来抵消石油生产和燃烧中的碳排放。采油量。