Analytical study of capture time to a horizontal well

We have investigated capture time through a horizontal well fur several types of aquifers. We have studied two scenarios in which wells are at the middle and at the bottom (or the top) of an aquifer. We have obtained the closed-form analytical solutions of capture times for these two scenarios in homogeneous, confined aquifers for both isotropic and anisotropic cases. We have discussed the applicability and the limitation of the analytical solutions. The presence of confining boundaries in vertical direction constrains the vertical flow, but enhances the horizontal Bow. The presence of anisotropy with a smaller vertical conductivity further limits the vertical Row and increases the horizontal Row. We have conducted numerical simulations to obtain capture times, and found that they were very close to the analytical solutions, given the same conditions. We have further analyzed the advantages and disadvantages of two different methods of simulating a horizontal well (uniform nux and uniform head). (C) 1999 Elsevier Science B.V. All rights reserved.