Fractured Rock Hydraulic Testing

A. Map of the location of test boreholes at the Toxic Substances Hydrology Program's Mirror Lake Fractured Rock Research Site, New Hampshire. The major water-producing fractures in each borehole were isolated with packers (inflatable rubber plugs). During the hydraulic test water was withdrawn from the upper fracture zone (FSE-6A) in the FSE-6 borehole.

B. Graph showing the hydraulic response of each fracture zone during the hydraulic test. Each colored line corresponds to the colored fracture zone conceptualized in C. The hydraulic response is the same in all the isolated borehole sections that intersect a single fracture zone. For example, the hydraulic responses of the borehole sections that isolate the red fracture zone are virtually identical.

C. A conceptualization of the hydraulic connections at the Mirror Lake Fractured Rock Research Site's borehole test area. Colored areas are high permeability fracture zones located within lower permeability (gray) fractured rock. The black rectangles are the locations of the borehole packers used to isolate fractures. As the pumping stress propagates through the lower permeability rock (gray area) the entire extent of each high permeability fracture zone responds at once as the wave of pumping stress encounters each zone in turn. This is also demonstrated in B. The fluid was pumped from the well field from the FSE-6A zone.