The CO₂ huff-n-puff experiments are often conducted on a rock sample with a given permeability. However, there is a need for understanding the production performance of CO₂ huff-n-puff over a range of rock permeability values. In this study, CO₂ huff-n-puff corefloods were conducted by using 30 cm long artificial cores over a permeability range between 0.7 and 240 mD. After that, the cores and produced oil were analyzed by NMT tests and gas chromatography tests. The effects of rock permeability on primary parameters, such as ultimate oil recovery, gas and oil ratio (GOR), pressures, residual oil distribution, and produced oil composition, were studied in detail. The experimental results indicate that the overall CO₂ huff-n-puff efficiency increases with permeability, while the production dynamics also changes with permeability. The oil production is greater and realized faster in high permeability core samples than low-permeability rocks; hence, maintaining the same production efficiency for low-permeability samples needs more production cycles and a longer production time. Fortunately, the GOR of CO₂ huff-n-puff in low-permeability samples is lower, which is favorable in long-term production. In contrast, a larger produced GOR is realized in high-permeability core samples, especially beyond the optimal cycle. Moreover, although the CO₂ front occurs at a shorter distance from the inlet as rock permeability decreases, CO₂ huff-n-puff can simultaneously produce oil from different pore sizes of different permeability core samples. The permeability of core samples also has a significant influence on the composition of the produced oil. The CO₂ extraction capability is stronger in samples with a lower permeability.

中文翻译：

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岩层渗透率与Huff-n-Puff CO2注入性能之间的相互作用。

通常在具有给定渗透率的岩石样品上进行CO ₂吞吐试验。然而，需要理解在一定的岩石渗透率值范围内CO ₂吞吐率的生产性能。在这项研究中，通过使用渗透率介于0.7至240 mD之间的30厘米长的人造岩心进行CO ₂吞吐-正喷扑岩心驱替。之后，通过NMT测试和气相色谱测试分析岩心和成品油。详细研究了岩石渗透率对主要参数的影响，例如最终采收率，气油比（GOR），压力，残余油分布和产出油组成。实验结果表明，总的CO ₂哈夫-n-puff效率随渗透率而增加，而生产动态也随渗透率而变化。与低渗透率岩石相比，高渗透率岩心样品的采油量更大，实现速度更快。因此，对于低渗透率样品保持相同的生产效率需要更长的生产周期和更长的生产时间。幸运的是，低渗透率样品中的CO ₂吞吐率正负值的GOR较低，这对于长期生产是有利的。相反，在高渗透率岩心样品中，尤其是超出最佳循环时，会实现更大的GOR。此外，尽管CO ₂前发生在从入口更短的距离如岩石渗透率降低，CO ₂huff-n-puff可同时从不同渗透率岩心样品的不同孔径生产油。岩心样品的渗透率也对产出油的组成有重要影响。在渗透率较低的样品中，CO _2的萃取能力较强。