导电性影响的地面核磁共振反演  

Nonlinear inversion of surface nuclear magnetic resonance over electrically conductive medium

作　　者：翁爱华[1] 王雪秋[1] 刘国兴[1] 莫修文[1] 王德利[1] 

机构地区：[1]吉林大学应用地球物理系,长春130026

出　　处：《地球物理学报》2007年第3期890-896,共7页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(40304009);吉林省杰出青年基金;国家油气专项资助(XQ-2004-07);国家油气资源战略选区调查与评价项目:大庆探区外围中;新生代断陷盆地群演化与油气远景联合资助

摘　　要：导电性影响对实际的地面核磁共振反演非常重要.在导电条件下,导出了地面核磁共振感应电动势的平方是含水率分布的二次型.通过进一步分析,我们将其对含水率的灵敏度用显式表示出来,为由核磁感应电动势利用迭代技术快速求解含水率分布奠定了理论基础.数值模拟结果表明,在自由空间与导电条件下,采用非线性反演技术获得的含水率分布与理论模型都有非常好的一致性.Electrical conductivity impacts the inversion of the data of surface nuclear magnetic resonance （NMR） sounding method. When the effect of electrical conductivity cannot be ignored, the square of the induced voltage of surface NMR can be expressed as a quadratic form involving water content as variables. Further analysis shows that the derivative of the square of the surface NMR voltage with respect to water content is of closed form. This makes nonlinear inversion of surface NMR data possible, and can speed up the inversion significantly. Numerical results show that the water content distribution resulted from nonlinear inversion agrees very well with the true model of both free space and electrically conductive medium.

关 键 词：地面核磁共振 导电性 非线性反演 灵敏度矩阵 找水 

分 类 号：P631[天文地球—地质矿产勘探]