$4\mathrm{.}11$ A fluid$-$flow problem in a porous medium is expressed by the

PDE$(de\frac{l}{d}$elx$)[1\mathrm{.}127A_x{k}_x(del\frac{p}{d}$elx$)]-0\mathrm{.}0433(de\frac{l}{d}$elx$)(1\mathrm{.}127A_x{k}_x)=0.$ If

properties of the flowing fluid are $=1cp,B=1R\frac{B}{S}TB,$ and

$=62\mathrm{.}4lb\frac{m}{f}{t}^3,$ describe the physical characteristics of the reser$-$

voir qualitatively and quantitatively.