FLUID FLOW PROPERTIES FROM ACOUSTICALLY STIMULATED NMR.

摘要

This invention is a method to measure fluid flow properties of a porous medium, including, but not limited to, the fluid flow permeability. In a preferred embodiment, the measurements are made down hole in drill wells exploring for hydrocarbons or acquifers. The measurement involves two types of instruments. One instrument creates a pressure wave (P) in the porous medium, which generates motion of the fluid in the pore space. The second instrument measures the fluid in the pore space using Nuclear Magnetic Resonance (NMR) methods. Any type of instrument that can generate a pressure gradient is suitable, including instruments that are remote from the NMR instrument. Magnetic field gradients (B) can be used to localize the NMR signal to a specific region within the porous medium. The magnetic field gradient (B) also provides the method by which the fluid motion is encoded on to the NMR signal. The permeability is calculated form the known pressure gradient (P) present in the porous medium by virtue of the applied pressure gradient or pressure wave and the velocity of the fluid in the rock pore space measured by NMR.