Sensitivity of dipole magnetic tomography to magnetic nanoparticle injectates

摘要: Abstract We compare the sensitivity of magnetic field measurements to perturbations permeability with conductivity alterations. The can be caused by different injected and formation resident fluid injecting nanoparticles. devise a simple method for calculating required solve parametric inverse problems in electromagnetic (EM) tomography involving perturbations. apply 3D 2D axisymmetric both crosswell single-well configurations homogeneous background. emphasis this paper is on acquired at very low induction numbers (kr ≪ 1; k being wave number r distance) where length or skin depth becomes an irrelevant scale. significantly higher than frequencies. Furthermore, low-frequency regime, largely independent frequency, unlike which improves consistent quasi-static dipole magnetics. patterns are quite different. four lobes opposite signs surrounding source receiver case provide opportunities vertical discrimination measurements. In configuration, perturbation larger close wellbore conductivity. Also, sign reversals real imaginary parts enhance horizontal geometry problem also affects sensitivities significantly. Both considered study. geometrical spreading perturbed region suppresses value permeability. exhibit when contrast agents proximity receivers (or near single-well). On other hand, EM more sensitive interwell off-wellbore system moderate high