Method and apparatus to incorporated internal gradient and restricted diffusion in NMR inversion

摘要

Pulse sequences are applied to a fluid in an earth formation with an external static magnetic field and NMR spin echo signals are obtained. The received NMR signals are affected by internal field gradients due to a contrast in magnetic susceptibility between the grains of the formation matrix and the fluid in the pore space. Processing of the data gives the relaxation time and diffusivity of the fluid.