69 Geophysics in the Central and Northeastern United States

Tuesday, 22 March 2011
1:30 PM - 5:30 PM
Lawrence Welk

VERY LOW FREQUENCY ELECTROMAGNETIC FRACTURE MAPPING FOR WATER RESOURCES

Paper number: 69-1
Program: Theme Sessions
Time: 1:30 PM – 1:45 PM

Authors

Abstract

Random drilling for commercially-productive groundwater wells is a haphazard method within the Pennsylvanian-aged rocks of the Appalachian Plateau Region of southwestern Pennsylvania. These rocks have low permeability and porosity and the average production well produces only enough yield for homeowner use. Often these wells are installed as an open hole to 300 feet to insure an adequate water supply for the homeowner since the well bore acts as a storage reservoir during recovery and drawdown.

Three sites mapped with Very Low Frequency (VLF) methods delineated fractures with the potential to maximize bedrock production through increased fracture-induced permeability. A boring was advanced from a location at each of the three sites selected through VLF mapping. The borings penetrated fractures at the anticipated depths of between 10 and 20 meters below grade. Pump tests indicate that these three borings can produce between over 1,000l/min with little drawdown. Each of the three wells is a commercial success.