Estimating the hydraulic properties of the fracture network in a sandstone aquifer.
The potential hydraulic behaviour of the fracture network in a major Triassic sandstone aquifer in the UK has been evaluated. The properties of the fracture network were determined using results from detailed scan line surveys at 10 sites, television and geophysical borehole logging, and packer testing. Six sets of discontinuities common to all sites were identified and statistically characterised (dip, strike, orientation, density, size, and estimated transmissivity). A discrete fracture network model was then used stochastically to investigate the properties of the network. In general, the network is poorly connected: it is estimated that 9% of the discontinuities intersecting boreholes are transmissive. The hydraulic behaviour of the network is generally dominated by one sub-horizontal bedding plane fracture set, although when present, a relatively infrequent north-south striking, sub-vertical set modifies the bulk flow properties significantly. Ignoring this latter set, the network's minimum representative volume is about 35 x 35 x 35 m. The upscaled permeability is anisotropic, being typically 23 times greater in the horizontal than in the vertical. Tortuosity in the north-south direction is around 1.6.
Hitchmough
Anna M
AM
Hydrogeology Research Group, Earth Sciences, School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Riley
Michael S
MS
Herbert
Alan W
AW
Tellam
John H
JH
D000465:Algorithms; D003198:Computer Simulation; D004784:Environmental Monitoring / Q000379:methods; D015233:Models, Statistical; D010539:Permeability; D012984:Software; D012987:Soil; D006113:United Kingdom; D014872:Water Movements; D014873:Water Pollutants; D014874:Water Pollutants, Chemical; D018508:Water Purification / Q000379:methods*; D014881:Water Supply
D012987:Soil; D014873:Water Pollutants; D014874:Water Pollutants, Chemical