Abstract Calculating hydrocarbon in place is one of the most important aspects to be considered in reservoir evaluation. Carbonate rocks with high heterogeneity, exhibit significant changes in petrophysical and lithological properties. Archie's exponents (m and a) are basic parameters for saturation calculations. Uncertainties in obtaining these exponents lead to considerable errors in the saturation assessment. In this study, various pore and rock typing methods were carried out on a Permian–Triassic carbonate reservoir in the central Persian Gulf, Iran. The used methods include pore typing, pore facies classification, velocity deviation log, reservoir quality index, Winland R35, Pittman R35 and ranges of core permeability. Archie's exponents were obtained for different classes based on extracted data from petrographical studies, conventional core analysis and wire line log data. Results showed that determination of rock types based on pore typing has the greatest effect on the precise determination of Archie's exponents. On the other hand, the most unreliable results were related to the velocity deviation log. Pore types directly control the connectivity of the fluid pathways and so have the most important effect. Combining pore types in various groups such as velocity deviation or pore facies classification, reduce the measurement accuracy of Archie's exponents and resulted water saturation. Finally, it can be concluded that, in addition to the high impact of pore type on the accuracy of the obtained exponents, the permeability and pore throat radius are less effective in determining the Archie's exponents.

中文翻译：

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碳酸盐岩储层非均质性对阿尔奇指数（a和m）的影响，以波斯湾中部康安和大兰气层为例

摘要 就地计算油气是储层评价中最重要的考虑因素之一。碳酸盐岩具有高度非均质性，岩石物理和岩性性质发生显着变化。Archie 指数（m 和 a）是饱和度计算的基本参数。获得这些指数的不确定性导致饱和度评估中的相当大的错误。在这项研究中，对伊朗波斯湾中部的二叠纪-三叠纪碳酸盐岩储层进行了各种孔隙和岩石分类方法。使用的方法包括孔隙类型、孔隙相分类、速度偏差测井、储层质量指数、Winland R35、Pittman R35和岩心渗透率范围。Archie 指数是根据从岩相研究中提取的数据获得的不同类别的指数，常规岩心分析和电缆测井数据。结果表明，基于孔隙类型的岩石类型确定对阿尔奇指数的精确确定影响最大。另一方面，最不可靠的结果与速度偏差日志有关。孔隙类型直接控制流体通路的连通性，因此具有最重要的影响。将速度偏差或孔隙相分类等不同组别的孔隙类型组合在一起，会降低阿奇指数的测量精度并导致含水饱和度。最后，可以得出结论，除了孔隙类型对所获得指数的准确性有很大影响外，渗透率和孔喉半径在确定 Archie 指数方面的效果较差。结果表明，基于孔隙类型的岩石类型确定对阿尔奇指数的精确确定影响最大。另一方面，最不可靠的结果与速度偏差日志有关。孔隙类型直接控制流体通路的连通性，因此具有最重要的影响。将速度偏差或孔隙相分类等不同组别的孔隙类型组合在一起，会降低阿奇指数的测量精度并导致含水饱和度。最后，可以得出结论，除了孔隙类型对所获得指数的准确性有很大影响外，渗透率和孔喉半径在确定 Archie 指数方面的效果较差。结果表明，基于孔隙类型的岩石类型确定对阿尔奇指数的精确确定影响最大。另一方面，最不可靠的结果与速度偏差日志有关。孔隙类型直接控制流体通路的连通性，因此具有最重要的影响。将速度偏差或孔隙相分类等不同组别的孔隙类型组合在一起，会降低阿奇指数的测量精度并导致含水饱和度。最后，可以得出结论，除了孔隙类型对所获得指数的准确性有很大影响外，渗透率和孔喉半径在确定 Archie 指数方面的效果较差。