Abstract Many of oil reservoirs have dealt with operational problems due to probability of asphaltene deposition as a consequence of asphaltene precipitation during natural production and gas injection into the reservoir. So the prediction of asphaltene precipitation is very important and many equations of state (such as Ping Robinson (PR) and Soave–Redlich–Kwong (SRK)) are used for this reason. These common equations are suitable for non-polar components and a modification is necessary to use them for prediction of asphaltene precipitation because of the polar nature of asphaltene compounds. In this study, the SRK equation of state was modified by deriving a new equation for calculating b-parameter (co-volume parameter); and this modified SRK equation of state was used to model asphaltene precipitation. Finally asphaltene precipitation during natural depletion and first stage gas injection process (in different concentrations), was monitored at reservoir temperature and various pressures. The experimental results show a good match with the modified SRK equation of state.

中文翻译：

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用于模拟沥青质沉淀的修正 SRK 状态方程

摘要 许多油藏由于自然生产过程中沥青质沉淀和向油藏注气导致沥青质沉积的可能性而处理了操作问题。因此，沥青质沉淀的预测非常重要，因此使用了许多状态方程（例如 Ping Robinson (PR) 和 Soave-Redlich-Kwong (SRK)）。这些常用方程适用于非极性组分，并且由于沥青质化合物的极性性质，需要对其进行修改才能将它们用于预测沥青质沉淀。在本研究中，通过推导一个新的计算b-参数（co-volume parameter）的方程来修改SRK状态方程；并且这个修正的 SRK 状态方程被用来模拟沥青质沉淀。最后，在储层温度和各种压力下监测自然枯竭和第一阶段注气过程中的沥青质沉淀（不同浓度）。实验结果表明与修正后的SRK状态方程匹配良好。