Effects of Nuclear Magnetic Resonance Frequency on the Transverse Relaxation Time of Altered Volcanic Rocks

doi:10.3969/j.issn.1006-6535.2023.02.003

Abstract

Abstract: In order to study the effect of frequency on the transverse chirality time T₂ of altered volcanic rocks, the altered volcanic rock samples from Longfeng Mountain area were selected for X-ray diffraction whole-rock and clay analysis, and NMR measurements at 2 MHz and 12 MHz were performed on representative samples. The results of the study show that the altered clay minerals are dominated by chlorite; the T₂ spectrum tends to shift to the left as the NMR frequency increases; this shift can lead to a false perception of the pore structure and can be corrected for the shift by the fitting formula. This correction method can guide the application of NMR instrument measurements at other frequencies in wells.

Key words: altered volcanic rocks, NMR, relaxation time, magnetic field gradient, chlorite

CLC Number:

TE357

Zhang Lihua, Pan Baozhi, Shan Gangyi, Wang Min, Cao Yue. Effects of Nuclear Magnetic Resonance Frequency on the Transverse Relaxation Time of Altered Volcanic Rocks[J]. Special Oil & Gas Reservoirs, 2023, 30(2): 20-25.

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