THE CHARACTERIZATION OF MULTIPHASE FLUID TRANSPORT IN A POROUS SOLID BY PULSED GRADIENT STIMULATED ECHO NUCLEAR-MAGNETIC-RESONANCE

Pulsed magnetic field gradient stimulated echo nuclear magnetic resona nce (NMR) measurements are reported for the steady-state flow and diff usion of two and three phases (water, dodecane, N-2 gas) within a samp le of a Fontainebleau sandstone. The stimulated echo dependence on the gradient pulse area, q, is used to derive the displacement probabilit y, P-Delta(X) for fixed observation times Delta, with the displacement s X being measured along the macroscopic pressure gradient. An extensi ve range of NMR experiments was carried out, starting with single-phas e flow of either water (an aqueous solution of NaCl 3% w/v) or oil (do decane) for various relative saturation states. Following these experi ments, P-Delta(X) were acquired for water and oil when both phases wer e forced to flow through the sandstone. Finally, NMR measurements were performed in which three phases (oil, water and N-2 gas) were flowing simultaneously. Using the NMR data it was possible to evaluate the ph ysical importance of parameters such as wettability, spreading and pha se saturations on the transport phenomena. To our knowledge, these exp eriments represent the first comprehensive NMR study of multiphase flo w in porous media, and the extent of the information obtained is provi ding a strong experimental basis to validate and develop accurate mode lling of fluid transport in porous solids. (C) 1998 American Institute of Physics.