Nuclear magnetic resonance T2 spectrum: multifractal characteristics and pore structure evaluation
| Autor: | Qinhong Hu, Bin Geng, Jian Ping Yan, Xu He, Xiao Pan Kou, Xing Wen Li, Chun Zhen Feng |
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| Rok vydání: | 2017 |
| Předmět: |
Materials science
020209 energy Petrophysics Mineralogy Multifractal spectra 02 engineering and technology Multifractal system 010502 geochemistry & geophysics 01 natural sciences Fractal dimension Spectral line Physics::Geophysics Geophysics Singularity Nuclear magnetic resonance 0202 electrical engineering electronic engineering information engineering 0105 earth and related environmental sciences |
| Zdroj: | Applied Geophysics. 14:205-215 |
| ISSN: | 1993-0658 1672-7975 |
| DOI: | 10.1007/s11770-017-0614-0 |
| Popis: | Pore structure characteristics are important to oil and gas exploration in complex low-permeability reservoirs. Using multifractal theory and nuclear magnetic resonance (NMR), we studied the pore structure of low-permeability sandstone rocks from the 4th Member (ES4) of the Shahejie Formation in the south slope of the Dongying Sag. We used the existing pore structure data from petrophysics, core slices, and mercury injection tests to classify the pore structure into three categories and five subcategories. Then, the T 2 spectra of samples with different pore structures were interpolated, and the one- and three-dimensional fractal dimensions and the multifractal spectrum were obtained. Parameters α (intensity of singularity) and f (α) (density of distribution) were extracted from the multifractal spectra. The differences in the three fractal dimensions suggest that the pore structure types correlate with α and f (α). The results calculated based on the multifractal spectrum is consistent with that of the core slices and mercury injection. Finally, the proposed method was applied to an actual logging profile to evaluate the pore structure of low-permeability sandstone reservoirs. |
| Databáze: | OpenAIRE |
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