The effect of carbonate reservoir heterogeneity on Archie's exponents (a and m), an example from Kangan and Dalan gas formations in the central Persian Gulf
| Autor: | Vahid Tavakoli, Maziyar Nazemi, Masoud Sharifi-Yazdi, Hossain Rahimpour-Bonab, Mehdi Hosseini |
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| Rok vydání: | 2018 |
| Předmět: |
Accuracy and precision
020209 energy Petrophysics Reservoir heterogeneity Energy Engineering and Power Technology Mineralogy 02 engineering and technology 010502 geochemistry & geophysics Geotechnical Engineering and Engineering Geology 01 natural sciences chemistry.chemical_compound Permeability (earth sciences) Fuel Technology chemistry Facies 0202 electrical engineering electronic engineering information engineering Carbonate Carbonate rock Saturation (chemistry) Geology 0105 earth and related environmental sciences |
| Zdroj: | Journal of Natural Gas Science and Engineering. 59:297-308 |
| ISSN: | 1875-5100 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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