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A Practical Method to Compensate the Effect of Echo Spacing on the Shale NMR T2 Spectrum
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 81st EAGE Conference and Exhibition 2019, Jun 2019, Volume 2019, p.1 - 5
Abstract
The effect of NMR responses influenced by the echo spacing (TE) is significant when applied to unconventional reservoirs such as shale. It is hard to achieve the precious porosity in downhole NMR measurement due to the long TE compared to the laboratory experiment. We develop a practical method to compensate the influence of TE on the transversal relaxation time (T2) spectrum of shale. Based on the experiments with different TE, the relationship between the NMR calibrated porosity and the TE is established to recover the amplitude. The effect of TE on the peak position is investigated and then an empirical equation is constructed to move the peak position to its original state. By the above two-step correction algorithm, the T2 spectrum of shale at large TE are compensated precisely. This method provides an effective way to obtain the real T2 spectrum, which is hopeful to apply to the downhole NMR data processing in shale reservoir.