摘要
导电模型的地面核磁共振感应电动势是含水量的非线性函数。引入模型约束的迭代反演方法求解该非线性问题的反演。在反演过程中,根据理论公式计算迭代过程中灵敏度矩阵,并采用平坦模型和光滑模型两种约束。对均匀半空间、层状导电模型和实际数据进行了反演模拟,结果表明,模型约束迭代反演方法能从地面核磁共振感应电动势获得含水层较为合理的含水量及分布,且该结果可以从作为初始模型的均匀含水量分布反演得到。对无噪音数据,平坦模型和光滑模型约束对反演的含水量分布影响不大;但当数据存在一定的噪音时,平坦模型约束将比光滑模型约束获得更为精确的含水层参数。
The induced voltage of surface nuclear magnetic resonance （NMR） based on conduction model is a nonlinear function of water content distribution. A model constrained linear iteration inversion method was introduced to dissolve the nonlinear problem. And during the inversion, two constrained models, flattest and smoothest model, were incorporated into the sensitivity matrix calculated by theoretical formula. The inversion simulation was taken for the homogeneous half space, layered conductive model data and field data. And the results showed that the model constrained iteration inversion methods can get more veliable water contents and distribution from the indued volotage of surface NMR, and these results can be inverted by model constrained inversion from an initial homogeneous water content model. For noise free surface NMR signals, both flattest and smoothest model constrained inversions can infer correct water content distributions. However, to noisy data, by smoothest model constrained inversion, the inferred water content became lower and distributed in a larger range than real model, which can be inverted by flattest model constrained inversion correctly.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2008年第4期692-697,共6页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(40304009)
关键词
地面核磁共振
模型约束
反演
导电性
地下水勘探
surface nuclear magnetic resonance
model constrain
inversion
electrically conductive medium
groundwater exploration
