FLUID-FLOW MEASUREMENT IN POROUS-MEDIA BY ECHO-PLANAR IMAGING

The study of fluid flow within porous solids is of great interest to the oil industry. However, these materials generally have physical characteristics which make them unsuitable for study by a conventional echo-planar imaging (EPI) sequence. Modifications to EPI which include 180° RF pulses have been implemented to make it suitable for imaging of these materials. A new flow-encoding sequence is also proposed which, in combination with modified EPI, allows full quantitative analysis of fluid velocities inside various sandstone samples. The flow-encoding technique minimizes signal loss due to translational diffusion and attenuates substantially the effect of locally induced field gradients, but maintains the sensitivity of a conventional bipolar velocity-encoding gradient. © 1992.