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The Impact of
Faults on Groundwater Flow Patterns in the Lower Rhine Embayment,
Bense, Victor1, Ronald Van Balen2
(1)
Faults have an
important impact groundwater flow in the unconsolidated sediments of the Lower
Rhine Embayment. In this area groundwater flow is strongly enhanced as a result
of the dewatering of deep (>400 m), open-pit mines that are explored for
lignite. Hydraulic head maps of this area show in detail how many individual
faults form a barrier to fluid flow while relay structures in these faults are
sites of hydraulic contact between otherwise separated aquifers. The Shale
Gouge Ratio (SGR) algorithm that relates fault throw and clay content of the
rock flanking the faults to its hydraulic properties,
was used to understand the variations in hydraulic behavior of the faults in
the study area in a systematic way. Although the application of this algorithm
is now rather common in hydrocarbon related studies it had not been applied to
groundwater flow data so far. Additionally, the effect of fault relay zones on
fluid flow in the area is assessed using numerical simulations of groundwater
flow. It is demonstrated that the SGR-methodology is a promising tool for the
estimation of fault zone hydraulic properties in hydrogeological
modeling. Moreover, we show the potential of groundwater flow data as an analog
to fluid flow in deeply buried reservoirs offshore, to better understand the
role of faults in hydrocarbon recovery related studies.