Unsteady Ground‐Water Flow Toward Extended Wells

Şen Z.

Groundwater, vol.30, no.1, pp.61-67, 1992 (Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 30 Issue: 1
  • Publication Date: 1992
  • Doi Number: 10.1111/j.1745-6584.1992.tb00812.x
  • Journal Name: Groundwater
  • Journal Indexes: Scopus
  • Page Numbers: pp.61-67
  • Istanbul Medipol University Affiliated: No


Ground‐water flow in naturally fractured rocks of low permeability terrain presents special problems which cannot be solved by classical radial flow techniques. Existence of fractures in these rocks increases the conductivity of the media, but the storativity does not increase significantly. Especially, a dominant vertical fracture in hydraulic connection with a well provides an extended surface for ground water to enter the well. Such a well and fracture combination is referred to as an “extended well.” The analytical approach to the ground‐water flow problem of extended wells cannot be achieved through merely radial or linear flow alone if the vertical fracture is of finite length. In fact, in practice, the fracture lengths are almost always of finite length, and the flow pattern is a mixture of radial and linear flows. This paper presents a simplified conceptual model for the ground‐water flow pattern around an extended well leading to an analytical solution with type curves which can be used in determining the aquifer parameters from the field measurements of time‐drawdown data. It is observed that for large times, extended well type curves merge with the Theis curve, and consequently the Jacob straight‐line method becomes applicable. In addition, as the vertical fracture length becomes smaller, the resulting type curve approaches the Theis type curve. The methodology has been applied for ground‐water flow in a folded and fractured limestone formation in the Conasauga Group of East Tennessee. Copyright © 1992, Wiley Blackwell. All rights reserved