The subject of the flow of homogeneous fluids-gases alone or gas-freeliquids-through porous media may be considered at the present time to be fairlywell completed. That is, analytical, graphical, numerical, or experimentalmethods are now available for obtaining detailed descriptions of the behaviorof such homogeneous fluid systems of any reasonable geometry. Thus, satisfactory empirical techniques are now well established for thedetermination of the permeability of porous media for homogeneous fluids, thenumerical magnitude of this permeability uniquely and completely describing aporous medium as a carrier of a homogeneous fluid.
Considering this constant as known, the treatment of a wide variety of specificproblems involving either the flow of gases or liquids has been carried throughto satisfactory conclusions. Beginning with the simple case of strictly radialtwo-dimensional flow of a liquid or gas into a well under steady-stateconditions, generalizations have been developed to apply for systems where theflow is not strictly radial, due either to a lack of uniformity in thereservoir pressures at points distant from the well or deviations fromcircularity of the external boundary. whereby the fluid is being supplied, andfinally, to the lack of complete penetration of the well into the producingstrata. Satisfactory descriptions are now available for cases where gravity isacting as the driving agent inducing the flow of liquid into the well, eitheralone or as a supplement to the effect of pressure. The effect of acidtreatment on limestone wells has been given a reasonable interpretation on thebasis of the fundamental theory of the flow of homogeneous fluids throughsands, as have the important features of the problem of water-coning.