TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractDoes Darcy's Law apply at the very low fluid velocities typical for petroleum reservoirs? There is a body of experimental evidence, primarily from non-petroleum disciplines, demonstrating departures from Darcy's Law at low fluid velocities -Pre-Darcy flow. If Pre-Darcy behavior occurs in oil & gas reservoirs, there could be substantial currently-unrecognized opportunities for increasing the economic recovery of hydrocarbons.