Abstract Through molecular dynamic simulation, an investigation was conducted into the behavioral mechanism of gas injection for the development of deep oil reservoirs, with the response to environment taken as the critical influencing factor in EOR. In this study, medium-shallow reservoir was used for comparative analysis, while two types of reservoir were examined in bulk phase and on mineral surface. It was found that in deep reservoirs, the type of gas made little difference to the oil dissolution in bulk phase. In contrast, there was an evident sequence, CO2 ≈ C3H8 > CH4 ≈ N2, observed during the process of oil detachment from mineral surface. In addition, the reservoir environment mainly affects the dissolution of long-chain components, because short-chain components will quickly reach a fully dissolved state. Our study highlights the effect of gas types on oil displacement on a molecular level, which may help to promote the development of deep oil reservoirs.

中文翻译：

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注气类型对深层油藏采收率的影响：分子动力学模拟研究

摘要 通过分子动力学模拟，以环境响应作为提高采收率的关键影响因素，研究了深部油藏开发注气行为机制。本研究采用中浅层储层进行对比分析，同时对两种类型的储层进行体相和矿物表面检测。研究发现，在深层储层中，气体类型对体相油溶蚀作用差异不大。相比之下，在石油从矿物表面脱离的过程中观察到了一个明显的顺序，CO2 ≈ C3H8 > CH4 ≈ N2。此外，储层环境主要影响长链组分的溶解，因为短链组分会很快达到完全溶解状态。