测井技术2025，Vol.49Issue(1)：31-39,9.DOI:10.16489/j.issn.1004-1338.2025.01.004
内部磁场梯度对火山岩二维核磁共振响应影响
Effect of the Internal Magnetic Field Gradient on Two Dimensional NMR Responses in Volcanic Rock
摘要
Abstract
Two dimensional(2D)nuclear magnetic resonance(NMR)technology can provide two kinds of relaxation information simultaneously,which has significant advantages in fluid identification and quantitative evaluation.There are rich paramagnetic minerals in volcanic reservoirs.Due to the difference in magnetic susceptibility,these paramagnetic minerals lead to a significant internal magnetic field gradient inside the rock,which affects the 2D NMR T1—T2 spectrum and D—T2 spectral response.In order to improve the reliability of 2D NMR logging interpretation,it is necessary to investigate the influence of internal magnetic field gradient on 2D NMR response.It is therefore necessary to study the effect of the internal magnetic field gradient on 2D NMR responses to improve the reliability of logging interpretation in volcanic reservoirs.The effect of the internal magnetic field gradient on 2D NMR T1—T2 and D—T2 responses was studied with the numerical simulation method,and an internal magnetic field gradient estimation method was proposed based on D—T2 spectra,and 2D NMR experiments were carried out to verify the simulation results in this paper.The results showed that oil,gas,clay bound water,capillary bound water,and movable water move towards the direction of T2 reduction,and their T1/T2 values significantly increase with the internal magnetic field gradient increases in 2D NMR T1—T2 spectra.Oil,gas,clay bound water,capillary bound water,and movable water move towards the increase direction of diffusion coefficient with the internal magnetic field gradient increases in 2D NMR D—T2 spectra.This is mainly because the internal magnetic field gradient is not considered in data inversion,leading to the erroneous assumption that the diffusion relaxation attenuation caused by the internal magnetic field gradient is due to an increase in diffusion coefficient.The accuracy of the internal magnetic field gradient estimation method was validated based the simulated D—T2 spectra.关键词
二维核磁共振/T1—T2/D—T2/火山岩/内部磁场梯度Key words
2D NMR/T1—T2/D—T2/volcanic rock/internal magnetic field gradient引用本文复制引用
崔式涛,赵永杰,肖飞,王磊,黄科,仁亚文,郭江峰..内部磁场梯度对火山岩二维核磁共振响应影响[J].测井技术,2025,49(1):31-39,9.基金项目
国家自然科学基金项目"页岩有机质核磁共振探测理论与评价方法研究"(42304118) （42304118）
中国石油天然气集团有限公司项目"含煤盆地富油煤岩石物理响应与测井方法研究"(D622990142) （D622990142）
中国石油集团测井有限公司项目"测井应用基础与前沿储备技术研究"(CNLC2022-9C) （CNLC2022-9C）
