Geometry of well capture zones in fractured media: uncertainties using an equivalent porous media approach

摘要

We aim to set up a methodology to establish a range of validity of the radial flow approach for fractured aquifers using a 2-D scenario with two families of fractures. At first, the parameters considered will be the size (radius) of the capture zone (r_cylinder)) in an equivalent homogeneous aquifer and the ratio of the hydraulic conductivity of fractures and rock matrix (K_(fract)/K_(rock)) We take as a master variable the maximum distance d_(max) from the pumping well to the isochrone. Results based in one realization show that, if the capture zone is sufficiently large, the fractured aquifer can be treated as a homogeneous porous media considering equivalent properties. Our preliminary simulations indicate that the cylinder formula r_(cylinder) can be applied to fractured aquifers providing reasonable (i.e. order of magnitude) estimates d_(max) for the range of K_(fract)/K_(rock)<20 studied here.