Gringarten-Ramey Solution for Fractured Aquifers with a Single Horizontal Plane Fracture
Description
A mathematical solution by Gringarten and Ramey (1974) is useful for determining the hydraulic properties (hydraulic conductivity, specific storage, hydraulic conductivity anisotropy and fracture radius) of fractured aquifers with a single horizontal plane fracture intersecting the control well. Analysis involves matching the solution to drawdown data collected during a pumping test. The solution estimates hydraulic conductivity anisotropy in a vertical (x-z) plane.
AQTESOLV provides visual and automatic methods for matching the Gringarten and Ramey solution to pumping test data. This easy-to-use and intuitive software promotes rapid and accurate determination of aquifer properties.
Assumptions
The following assumptions apply to the use of the Gringarten and Ramey horizontal fracture solution:
- aquifer has infinite areal extent
- aquifer has uniform thickness
- aquifer potentiometric surface is initially horizontal
- fractured aquifer represented by anisotropic nonleaky confined system with a single plane horizontal fracture
- flow is unsteady
- water is released instantaneously from storage with decline of hydraulic head
- diameter of control well is very small so that storage in the well can be neglected
Solution Options
AQTESOLV provides the following options for the Gringarten and Ramey horizontal fracture solution:
- variable pumping rates
- multiple pumping wells
- multiple observation wells
Benchmark
Comparison of AQTESOLV (blue line) and published uniform-flux horizontal plane fracture well function values (symbols) at the wellbore for hD=1 and zD=0.5 (Gringarten and Ramey 1974).
References
Gringarten, A.C. and H.J. Ramey, 1974. Unsteady state pressure distributions created by a well with a single horizontal fracture, partial penetration or restricted entry, SPE Journal, pp. 413-426.
See also: solution methods, pumping tests