摘要：Nuclear magnetic resonance (NMR) logging provides key parameters for reservoir evaluation and production operations. In the design of an NMR logging tool, the combination of inhomogeneous static magnetic and radio frequency (RF) fields results in a complex signal distribution. Matching the two magnetic fields allows one to accurately calculate the sensitive volume of the probe and estimate the signal amplitude. The structure of the RF coil is typically optimized to match the static field via a time-consuming procedure. In this study, a magnetic-charge model is used to calculate the static magnetic field of a simplified square-shaped magnet. Subsequently, the target-field method is used to design the RF coil for matching the specific static magnet field generated by the magnet. The designed coil provides a more homogeneous NMR signal in the azimuthal orientation. A cylindrical slice with a height of 100 and 32 mm from the axis of symmetry constitutes the sensitive volume of the probe. To assess the detection effectiveness of the probe, 1-D and 2-D NMR experiments are conducted using copper-sulfate solutions and white-oil samples with different viscosities. The high-gradient magnetic field (i.e., 3.2 T/m) of the probe is used to facilitate diffusion coefficient measurements for high-viscosity fluids.

关键字：Magnetic resonance imaging; Magnetostatics; Nuclear magnetic resonance; Magnetic field measurement; Saturation magnetization; Probes; Coils; Radio frequency; Permanent magnets; Signal to noise ratio; Coil inversion design; low-field nuclear magnetic resonance (NMR); signal-to-noise ratio (SNR); target-field method

ISSN号：0018-9456

卷、期、页：卷73

发表日期：2024-09-30

期刊分区（SCI为中科院分区）：二区

收录情况：SCI（科学引文索引印刷版）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：IEEE Transactions on Instrumentation and Measurement

参与作者：刘化冰,赵晓光

通讯作者：龙志豪

第一作者：肖立志,罗嗣慧

论文类型：期刊论文

论文概要：龙志豪,肖立志,罗嗣慧,刘化冰,赵晓光，Inverse Design of RF Coil for Slim Nuclear Magnetic Resonance Logging Tool，IEEE Transactions on Instrumentation and Measurement，2024，卷73

论文题目：Inverse Design of RF Coil for Slim Nuclear Magnetic Resonance Logging Tool